KR20210105984A - Intra random access point pictures and leading pictures in video coding - Google Patents

Abstract

A method of encoding a video bitstream implemented by a video encoder is disclosed. The method includes: storing in a memory of a video encoder a set of less than five network abstraction layer (NAL) unit types available for video data; selecting, by a processor of a video encoder, a NAL unit type from a set of less than 5 NAL unit types for a picture from the video data; generating, by a processor of a video encoder, a video bitstream that includes a NAL unit corresponding to the selected NAL unit type and includes an identifier identifying the selected NAL unit type; and sending, by the transmitter of the video encoder, the video bitstream towards the video decoder. A corresponding method of decoding a video bitstream is also disclosed.

Description

Intra random access point pictures and leading pictures in video coding

Cross-referencing of related applications

This patent application is entitled "On Intra Random Access Point Pictures and Leading Pictures in Video Coding," U.S. Provisional Application No., filed December 27, 2018 by Fnu Hendry et al., which is incorporated herein by reference. Claims the interests of No. 62/785,515.

In general, this disclosure describes techniques for processing network abstraction layer (NAL) unit types for leading and intra random access point (IRAP) pictures. More specifically, this disclosure describes techniques for limiting the number of available NAL unit types and using flags to indicate whether a picture is decodable when the pictures are not identified by a NAL unit type.

The amount of video data required to depict a relatively short video can be significant, which can create difficulties when the data is streamed or otherwise conveyed over a communication network having limited bandwidth capacity. Accordingly, video data is typically compressed prior to delivery over modern communication networks. The size of the video may be an issue when the video is stored on a storage device because memory resources may be limited. Video compression devices often code the video data using software and/or hardware at the source prior to transmission or storage, thereby reducing the amount of data required to represent digital video images prior to transmission or storage. The compressed data is then received at the destination by a video decompression device that decodes the video data. As limited network resources and the demand for higher video quality continue to increase, improved compression and decompression techniques that improve compression ratios with little or no sacrificing image quality are desirable.

A first aspect relates to a method of encoding a video bitstream implemented by a video encoder. The method includes storing a set (a set of less than five network abstraction layer (NAL) unit types) of less than five possible network abstraction layer (NAL) unit type of use for the video data to the video encoder memory; selecting, by a processor of a video encoder, a NAL unit type from a set of less than 5 NAL unit types for a picture from the video data; generating, by a processor of a video encoder, a video bitstream that includes a NAL unit corresponding to the selected NAL unit type and includes an identifier identifying the selected NAL unit type; and sending, by the transmitter of the video encoder, the video bitstream towards the video decoder.

This method provides techniques for limiting the set of NAL unit types available for video data to no more than 5 specific NAL unit types (eg, limiting the number of NAL unit types to 4). This allows leading and trailing pictures (aka, non-IRAP pictures) to share the same NAL unit type. This also allows NAL unit types to indicate whether an I-RAP picture is associated with a RADL picture and/or a RASL picture. Additionally, certain NAL unit types may be mapped to different SAP types in DASH. By constraining the set of NAL unit types, the coder/decoder (aka “codec”) in video coding is improved over current codecs (eg, uses fewer bits, requires less bandwidth, and is more efficient, etc.). In practice, the improved video coding process provides a better user experience for the user when transmitting, receiving and/or watching video.

Thus, in a first implementation form of the method according to the first aspect, the set of less than 5 network abstraction layer (NAL) unit types include: leading and trailing pictures NAL unit type, random access skipped leading; Intra Random Access Point (IRAP) with RASL) NAL unit type, IRAP with random access decodable leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type.

In a second implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, the set of less than five network abstraction layer (NAL) unit types are: leading and trailing pictures NAL unit type, random It consists of an Intra Random Access Point (IRAP) with Access Skip Type Leading (RASL) NAL unit type, IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type.

In a third implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, both the leading and trailing pictures are assigned the leading and trailing pictures NAL unit type.

In a fourth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, having a RASL NAL unit type for an IRAP picture followed by one or more RASL pictures and zero or more RADL pictures in decoding order IRAP is selected.

In a fifth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, the IRAP picture is referred to as a clean random access (CRA) picture.

In a sixth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, the IRAP having a RASL NAL unit type is referred to as a Clean Random Access (CRA) NAL unit type.

In a seventh implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, an IRAP having a RASL NAL unit type is designated as IRAP_W_RASL.

In an eighth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, the IRAP_W_RASL designation is: Stream Access Point (SAP) Type 3 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol respond to

In a ninth implementation form of the method according to the first aspect or any preceding implementation of the first aspect, having a RADL NAL unit type for an IRAP picture followed by one or more RADL pictures and zero or more RADL pictures in decoding order IRAP is selected.

In a tenth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture.

In an eleventh implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, an IRAP with a RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with a RADL NAL unit type.

In a twelfth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, an IRAP having a RADL NAL unit type is designated as IRAP_W_RADL.

In a thirteenth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, IRAP_W_RADL corresponds to Stream Access Point (SAP) Type 2 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol do.

In a fourteenth implementation of the method according to the first aspect or any preceding implementation of the first aspect, an IRAP having no leading pictures NAL unit type is selected for an IRAP picture not followed by a leading picture in decoding order . In a fifteenth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture.

In a sixteenth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, IRAP without leading pictures NAL unit type is called Instantaneous Decoder Refresh (IDR) without leading pictures NAL unit type. is referred to

In a seventeenth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, an IRAP without leading pictures NAL unit type is designated as IRAP_N_LP.

In an eighteenth implementation form of the method according to the first aspect or any preceding implementation form of the first aspect, the IRAP_N_LP designation is in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol to Stream Access Point (SAP) Type 1 respond

A second aspect relates to a method of decoding a coded video bitstream implemented by a video decoder. The method includes storing in a memory of a video decoder a set of less than five network abstraction layer (NAL) unit types available for video data; receiving, by a receiver of a video decoder, a coded video bitstream comprising a NAL unit and an identifier; determining, by a processor of the video decoder, a NAL unit type used to encode the NAL unit based on the identifier from the set of less than five NAL unit types; and allocating, by a processor of the video decoder, a presentation order for pictures included in the NAL unit based on the determined NAL unit type.

This method provides techniques for limiting the set of NAL unit types available for video data to no more than 5 specific NAL unit types (eg, limiting the number of NAL unit types to 4). This allows leading and trailing pictures (aka, non-IRAP pictures) to share the same NAL unit type. This also allows NAL unit types to indicate whether an I-RAP picture is associated with a RADL picture and/or a RASL picture. Additionally, certain NAL unit types may be mapped to different SAP types in DASH. By constraining the set of NAL unit types, the coder/decoder (aka “codec”) in video coding is improved over current codecs (eg, uses fewer bits, requires less bandwidth, and is more efficient, etc.). In practice, the improved video coding process provides a better user experience for the user when transmitting, receiving and/or watching video.

Thus, in a first implementation form of the method according to the second aspect, the set of less than 5 network abstraction layer (NAL) unit types are: leading and trailing pictures NAL unit type, random access skipping leading (RASL) NAL unit type Intra Random Access Point (IRAP) with , IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type.

In a second implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, the set of less than five network abstraction layer (NAL) unit types are: leading and trailing pictures NAL unit type, random It consists of an Intra Random Access Point (IRAP) with Access Skip Type Leading (RASL) NAL unit type, IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type.

In a third implementation of the method according to the second aspect or any preceding implementation of the second aspect, both the leading and trailing pictures are assigned the leading and trailing pictures NAL unit type.

In a fourth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, having a RASL NAL unit type for an IRAP picture followed by one or more RASL pictures and zero or more RADL pictures in decoding order IRAP is determined.

In a fifth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, the IRAP picture is referred to as a clean random access (CRA) picture.

In a sixth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, the IRAP having a RASL NAL unit type is referred to as a Clean Random Access (CRA) NAL unit type.

In a seventh implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, an IRAP having a RASL NAL unit type is designated as IRAP_W_RASL.

In an eighth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, the IRAP_W_RASL designation is: Stream Access Point (SAP) Type 3 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol respond to

In a ninth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, having a RADL NAL unit type for an IRAP picture followed by one or more RADL pictures and zero or more RADL pictures in decoding order IRAP is determined.

In a tenth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture.

In an eleventh implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, an IRAP with a RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with a RADL NAL unit type.

In a twelfth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, an IRAP having a RADL NAL unit type is designated as IRAP_W_RADL.

In a thirteenth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, IRAP_W_RADL corresponds to Stream Access Point (SAP) Type 2 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol do.

In a fourteenth implementation of the method according to the second aspect or any preceding implementation of the second aspect, an IRAP having no leading pictures NAL unit type is determined for an IRAP picture not followed by a leading picture in decoding order .

In a fifteenth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture.

In a sixteenth implementation form of the method according to the second aspect or any preceding implementation form of the second aspect, IRAP without leading pictures NAL unit type is called Instantaneous Decoder Refresh (IDR) without leading pictures NAL unit type. is referred to

In a seventeenth implementation of the method according to the second aspect or any preceding implementation of the second aspect, an IRAP without leading pictures NAL unit type is designated as IRAP_N_LP.

In an eighteenth implementation form of the method according to the second aspect or any preceding implementation of the second aspect, the IRAP_N_LP designation is in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol to Stream Access Point (SAP) Type 1 respond

A third aspect relates to an encoding device. The encoding device comprises: a memory including a set of less than five network abstraction layer (NAL) unit types usable for instructions and video data; A processor coupled to the memory, the processor causing the encoding device to: select a NAL unit type from a set of less than five NAL unit types for a picture from the video data; configured to implement instructions to generate a video bitstream that includes a NAL unit corresponding to the selected NAL unit type and includes an identifier identifying the selected NAL unit type; and a transmitter coupled to the processor and configured to transmit the video bitstream towards the video decoder.

The encoding device provides techniques for limiting the set of NAL unit types available for video data to no more than 5 specific NAL unit types (eg, limiting the number of NAL unit types to 4). This allows leading and trailing pictures (aka, non-IRAP pictures) to share the same NAL unit type. This also allows NAL unit types to indicate whether an I-RAP picture is associated with a RADL picture and/or a RASL picture. Additionally, certain NAL unit types may be mapped to different SAP types in DASH. By constraining the set of NAL unit types, the coder/decoder (aka “codec”) in video coding is improved over current codecs (eg, uses fewer bits, requires less bandwidth, and is more efficient, etc.). In practice, the improved video coding process provides a better user experience for the user when transmitting, receiving and/or watching video.

In a first implementation form of the encoding device according to the third aspect, the set of less than five network abstraction layer (NAL) unit types are: leading and trailing pictures NAL unit type, random access skipping leading (RASL) NAL unit type Intra Random Access Point (IRAP) with , IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type.

In a second implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, the set of less than five network abstraction layer (NAL) unit types comprises: leading and trailing pictures NAL unit type; Consists of Intra Random Access Point (IRAP) with Random Access Skip Type Leading (RASL) NAL unit type, IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. .

In a third implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, both the leading and trailing pictures are assigned the leading and trailing pictures NAL unit type.

In a fourth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, the RASL NAL unit type is configured for an IRAP picture followed by one or more RASL pictures and zero or more RADL pictures in decoding order. The IRAP with which it has is selected.

In a fifth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, the IRAP picture is referred to as a clean random access (CRA) picture.

In a sixth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, the IRAP having a RASL NAL unit type is referred to as a clean random access (CRA) NAL unit type.

In a seventh implementation form of the encoding device according to the third aspect or any preceding implementation aspect of the third aspect, an IRAP having a RASL NAL unit type is designated as IRAP_W_RASL.

In an eighth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, the IRAP_W_RASL designation is: Stream Access Point (SAP) type in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol corresponds to 3.

In a ninth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, the RADL NAL unit type is configured for an IRAP picture followed by one or more RADL pictures and zero or more RADL pictures in decoding order. The IRAP with which it has is selected.

In a tenth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture.

In the eleventh implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, an IRAP with a RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with a RADL NAL unit type.

In a twelfth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, an IRAP having a RADL NAL unit type is designated as IRAP_W_RADL.

In a thirteenth implementation form of the encoding device according to the third aspect or any preceding implementation aspect of the third aspect, IRAP_W_RADL is: Stream Access Point (SAP) Type 2 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol respond to

In a fourteenth implementation form of the encoding device according to the third aspect or any preceding implementation aspect of the third aspect, an IRAP having no leading pictures NAL unit type is selected for an IRAP picture not followed by a leading picture in decoding order do.

In a fifteenth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture.

In a sixteenth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, IRAP without leading pictures NAL unit type is an instantaneous decoder refresh (IDR) without leading pictures NAL unit type. is referred to as

In a seventeenth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, an IRAP having no lead pictures NAL unit type is designated as IRAP_N_LP.

In an eighteenth implementation form of the encoding device according to the third aspect or any preceding implementation form of the third aspect, the IRAP_N_LP designation is: Stream Access Point (SAP) type in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol corresponds to 1.

A fourth aspect relates to a decoding device. The decoding device includes: a receiver configured to receive a coded video bitstream that includes a NAL unit and an identifier; a memory coupled to the receiver, the memory storing instructions and sets of less than five network abstraction layer (NAL) unit types available for video data; and a processor coupled to the memory, the processor configured to cause the decoding device to: determine from the set of less than five NAL unit types a NAL unit type used to encode the NAL unit based on the identifier; and execute instructions to assign a presentation order to pictures included in the NAL unit based on the determined NAL unit type.

The decoding device provides techniques for limiting the set of NAL unit types available for video data to no more than 5 specific NAL unit types (eg, limiting the number of NAL unit types to 4). This allows leading and trailing pictures (aka, non-IRAP pictures) to share the same NAL unit type. This also allows NAL unit types to indicate whether an I-RAP picture is associated with a RADL picture and/or a RASL picture. Additionally, certain NAL unit types may be mapped to different SAP types in DASH. By constraining the set of NAL unit types, the coder/decoder (aka “codec”) in video coding is improved over current codecs (eg, uses fewer bits, requires less bandwidth, and is more efficient, etc.). In practice, the improved video coding process provides a better user experience for the user when transmitting, receiving and/or watching video.

In a first implementation form of the decoding device according to the fourth aspect, the set of less than five network abstraction layer (NAL) unit types are: leading and trailing pictures NAL unit type, random access skipping leading (RASL) NAL unit type Intra Random Access Point (IRAP) with , IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type.

In the second implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, the set of less than five network abstraction layer (NAL) unit types comprises: leading and trailing pictures NAL unit type; Consists of Intra Random Access Point (IRAP) with Random Access Skip Type Leading (RASL) NAL unit type, IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. .

In a third implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, both the leading and trailing pictures are assigned the leading and trailing pictures NAL unit type.

In a fourth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, the RASL NAL unit type is selected for an IRAP picture followed by one or more RASL pictures and zero or more RADL pictures in decoding order. The IRAP with which it has is selected.

In a fifth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, the IRAP picture is referred to as a clean random access (CRA) picture.

In a sixth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, the IRAP having a RASL NAL unit type is referred to as a clean random access (CRA) NAL unit type.

In a seventh implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, an IRAP having a RASL NAL unit type is designated as IRAP_W_RASL.

In an eighth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, the IRAP_W_RASL designation is: Stream Access Point (SAP) type in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol corresponds to 3.

In a ninth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, having a RADL NAL unit type for an IRAP picture followed by one or more RADL pictures and zero RADL pictures in decoding order IRAP is selected.

In a tenth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture.

In the eleventh implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, the IRAP with the RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with the RADL NAL unit type.

In a twelfth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, an IRAP having a RADL NAL unit type is designated as IRAP_W_RADL.

In a thirteenth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, IRAP_W_RADL is: Stream Access Point (SAP) Type 2 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol respond to

In a fourteenth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, an IRAP having no leading pictures NAL unit type is selected for an IRAP picture not followed by a leading picture in decoding order do.

In a fifteenth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture.

In a sixteenth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, IRAP without leading pictures NAL unit type is an instantaneous decoder refresh (IDR) without leading pictures NAL unit type. is referred to as

In a seventeenth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, an IRAP having no lead pictures NAL unit type is designated as IRAP_N_LP.

In an eighteenth implementation form of the decoding device according to the fourth aspect or any preceding implementation form of the fourth aspect, the IIRAP_N_LP designation is: Stream Access Point (SAP) type in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol corresponds to 1.

A fifth aspect relates to a method of encoding a video bitstream implemented by a video encoder. The method includes, by a processor of a video encoder, generating, for a non-IRAP picture associated with an intra random access point (IRAP) picture, a bitstream comprising NAL units; When the NAL unit for a non-intra random access point (non-IRAP) picture contains a random access decodable leading (RADL) picture, by the processor of the video encoder, a first flag in the bitstream is set setting to a first value; when the NAL unit for the non-IRAP picture includes a random access skipping leading (RASL) picture, setting, by a processor of the video encoder, a second flag in the bitstream to a first value; and sending, by the transmitter of the video encoder, the video bitstream towards the video decoder.

This encoding method provides techniques for the case where non-IRAP pictures are not identified by NAL unit type. In this case, the flags in the bitstream are set to a specific value indicating whether the IRAP picture is associated with a RADL picture or a RASL picture.

In a first implementation form of the method according to the fifth aspect, the first flag is designated as RadlPictureFlag and the second flag is designated as RaslPictureFlag.

In a second implementation of the method according to the fifth aspect or any preceding implementation of the fifth aspect, the first value is one (1).

In a third implementation form of the method according to the fifth aspect or any preceding implementation form of the fifth aspect, the non-IRAP picture comprises a leading picture.

In a fourth implementation form of the method according to the fifth aspect or any preceding implementation form of the fifth aspect, the non-IRAP picture comprises a trailing picture.

In a fifth implementation form of the method according to the fifth aspect or any preceding implementation form of the fifth aspect, the first flag is: when a picture order count (POC) value of a non-IRAP picture is less than a POC value of an IRAP picture It is set equal to the first value.

In a sixth implementation form of the method according to the fifth aspect or any preceding implementation form of the fifth aspect, the first flag indicates that each reference picture list for a non-IRAP picture is an IRAP picture associated with a non-IRAP picture or It is set equal to the first value when it does not include any pictures other than another RADL picture associated with the IRAP picture.

In a seventh implementation form of the method according to the fifth aspect or any preceding implementation form of the fifth aspect, the second flag is the second flag when the POC value of the non-IRAP picture is less than the picture order count (POC) value of the IRAP picture. It is set equal to 1 value.

In an eighth implementation form of the method according to the fifth aspect or any preceding implementation aspect of the fifth aspect, the second flag indicates that the reference picture list for the non-IRAP picture is an IRAP picture associated with the non-IRAP picture in decoding order. Or, when including at least one reference picture preceding another RASL picture associated with the IRAP picture, it is set equal to the first value.

In a ninth implementation form of the method according to the fifth aspect or any preceding implementation form of the fifth aspect, the first flag and the second flag are configured such that the NAL unit for a non-IRAP picture does not contain a RADL picture or a RASL picture. and setting it to a second value indicating that it is not.

In a tenth implementation form of the method according to the fifth aspect or any preceding implementation form of the fifth aspect, neither the first flag nor the second flag are set to the first value for the non-IRAP picture.

A sixth aspect relates to a method of decoding a video bitstream implemented by a video decoder. The method comprises, by a receiver of a video decoder, a coded video comprising a first flag, a second flag and a NAL unit for a non-intra random access point (non-IRAP) picture associated with an intra random access point (IRAP) picture. receiving a bitstream; determining, by a processor of the video decoder, that the NAL unit for the non-IRAP picture contains a random access decodable leading (RADL) picture when a first flag in the bitstream is set to a first value; ; determining, by a processor of the video decoder, that the NAL unit for the non-IRAP picture includes a random access skip-type lead (RASL) picture when a second flag in the bitstream is set to a first value; and assign, by the processor of the video decoder, a presentation order for pictures included in the NAL unit based on the first flag or the second flag having the first value, and decode the NAL unit based on the assigned presentation order. including the steps of

This decoding method provides techniques for the case where non-IRAP pictures are not identified by NAL unit type. In this case, the flags in the bitstream are set to a specific value indicating whether the IRAP picture is associated with a RADL picture or a RASL picture.

In a first implementation form of the method according to the sixth aspect, the first flag is designated as RadlPictureFlag and the second flag is designated as RaslPictureFlag.

In a second implementation of the method according to the sixth aspect or any preceding implementation of the sixth aspect, the first value is one (1).

In a third implementation form of the method according to the sixth aspect or any preceding implementation form of the sixth aspect, the non-IRAP picture comprises a leading picture.

In a fourth implementation form of the method according to the sixth aspect or any preceding implementation form of the sixth aspect, the non-IRAP picture comprises a trailing picture.

In a fifth implementation form of the method according to the sixth aspect or any preceding implementation form of the sixth aspect, the first flag is: when a picture order count (POC) value of a non-IRAP picture is less than a POC value of an IRAP picture It is set equal to the first value.

In a sixth implementation form of the method according to the sixth aspect or any preceding implementation form of the sixth aspect, the first flag indicates that each reference picture list for a non-IRAP picture is an IRAP picture associated with a non-IRAP picture or It is set equal to the first value when it does not include any pictures other than another RADL picture associated with the IRAP picture.

In a seventh implementation form of the method according to the sixth aspect or any preceding implementation form of the sixth aspect, the second flag is the second flag when the picture order count (POC) value of the non-IRAP picture is less than the POC value of the IRAP picture. It is set equal to 1 value.

In an eighth implementation form of the method according to the sixth aspect or any preceding implementation form of the sixth aspect, the second flag indicates that the reference picture list for the non-IRAP picture is an IRAP picture associated with the non-IRAP picture in decoding order. Or, when including at least one reference picture preceding another RASL picture associated with the IRAP picture, it is set equal to the first value.

In a ninth implementation form of the method according to the sixth aspect or any preceding implementation form of the sixth aspect, the first flag and the second flag are configured such that the NAL unit for a non-IRAP picture does not contain a RADL picture or a RASL picture. and setting it to a second value indicating that it is not.

In a tenth implementation form of the method according to the sixth aspect or any preceding implementation form of the sixth aspect, neither the first flag nor the second flag are set to the first value for the non-IRAP picture.

A seventh aspect relates to a coding apparatus. A coding apparatus includes: a receiver configured to receive a bitstream to be decoded; a transmitter coupled to the receiver and configured to transmit the decoded image to a display; a memory coupled to at least one of the receiver or the transmitter and configured to store instructions; and a processor coupled to the memory, wherein the processor is configured to execute instructions stored in the memory to perform the method of any embodiment disclosed herein.

The coding apparatus provides techniques for limiting the set of NAL unit types available for video data to no more than 5 specific NAL unit types (eg, limiting the number of NAL unit types to 4). This allows leading and trailing pictures (aka, non-IRAP pictures) to share the same NAL unit type. This also allows NAL unit types to indicate whether an I-RAP picture is associated with a RADL picture and/or a RASL picture. Additionally, certain NAL unit types may be mapped to different SAP types in DASH. By constraining the set of NAL unit types, the coder/decoder (aka “codec”) in video coding is improved over current codecs (eg, uses fewer bits, requires less bandwidth, and is more efficient, etc.). In practice, the improved video coding process provides a better user experience for the user when transmitting, receiving and/or watching video.

The coding apparatus also provides techniques for the case where non-IRAP pictures are not identified by NAL unit type. In this case, the flags in the bitstream are set to a specific value indicating whether the IRAP picture is associated with a RADL picture or a RASL picture.

An eighth aspect relates to a system. The system includes an encoder; and a decoder in communication with the encoder, wherein the encoder or decoder comprises a decoding device, encoding device, or coding apparatus disclosed herein.

This system provides techniques for limiting the set of NAL unit types available for video data to no more than 5 specific NAL unit types (eg, limiting the number of NAL unit types to 4). This allows leading and trailing pictures (aka, non-IRAP pictures) to share the same NAL unit type. This also allows NAL unit types to indicate whether an I-RAP picture is associated with a RADL picture and/or a RASL picture. Additionally, certain NAL unit types may be mapped to different SAP types in DASH. By constraining the set of NAL unit types, the coder/decoder (aka “codec”) in video coding is improved over current codecs (eg, uses fewer bits, requires less bandwidth, and is more efficient, etc.). In practice, the improved video coding process provides a better user experience for the user when transmitting, receiving and/or watching video.

The system also provides techniques for the case where non-IRAP pictures are not identified by NAL unit type. In this case, the flags in the bitstream are set to a specific value indicating whether the IRAP picture is associated with a RADL picture or a RASL picture.

A ninth aspect relates to means for coding. The means for coding comprises: receiving means configured to receive a bitstream to be decoded; transmitting means coupled to the receiving means and configured to transmit the decoded image to the display means; storage means coupled to at least one of the receiving means or the transmitting means and configured to store instructions; and processing means coupled to the storage means, wherein the processing means is configured to execute the instructions stored in the storage means to perform the methods disclosed herein.

Means for coding provides techniques for limiting the set of NAL unit types available for video data to no more than 5 specific NAL unit types (eg, limiting the number of NAL unit types to 4). This allows leading and trailing pictures (aka, non-IRAP pictures) to share the same NAL unit type. This also allows NAL unit types to indicate whether an I-RAP picture is associated with a RADL picture and/or a RASL picture. Additionally, certain NAL unit types may be mapped to different SAP types in DASH. By constraining the set of NAL unit types, the coder/decoder (aka “codec”) in video coding is improved over current codecs (eg, uses fewer bits, requires less bandwidth, and is more efficient, etc.). In practice, the improved video coding process provides a better user experience for the user when transmitting, receiving and/or watching video.

Means for coding also provides techniques for the case where non-IRAP pictures are not identified by NAL unit type. In this case, the flags in the bitstream are set to a specific value indicating whether the IRAP picture is associated with a RADL picture or a RASL picture.

For a more complete understanding of the present disclosure, reference is now made to the following brief description and detailed description directed to the accompanying drawings in which like reference numerals indicate like parts.
1 is a block diagram illustrating an example coding system that may utilize bi-directional prediction techniques.
2 is a block diagram illustrating an example video encoder that may implement bidirectional prediction techniques.
3 is a block diagram illustrating an example of a video decoder that may implement bidirectional prediction techniques.
4 is a schematic diagram of one embodiment of a video bitstream;
5 is a representation of the relationship between the I-RAP picture with respect to leading pictures and trailing pictures in decoding order and presentation order.
6 is an embodiment of a method for encoding a video bitstream.
7 is an embodiment of a method for decoding a coded video bitstream.
8 is an embodiment of a method for encoding a video bitstream.
9 is an embodiment of a method for decoding a coded video bitstream.
10 is a schematic diagram of a video coding device;
11 is a schematic diagram of one embodiment of a means for coding;

The following are various abbreviations used herein: Coding Tree Block (CTB), Coding Tree Unit (CTU), Coding Unit (CU), Coded Video Sequence (CVS) ), Joint Video Experts Team (JVET), Motion-Constrained Tile Set (MCTS), Maximum Transfer Unit (MTU), Network Abstraction Layer (NAL) ), Picture Order Count (POC), Picture Parameter Set (PPS), Raw Byte Sequence Payload (RBSP), Sequence Parameter Set (SPS), Versatile Versatile Video Coding (VVC) and Working Draft (WD).

1 is a block diagram illustrating an example coding system 10 that may utilize the video coding techniques described herein. As shown in FIG. 1 , the coding system 10 includes a source device 12 that provides encoded video data to be decoded later by a destination device 14 . In particular, source device 12 may provide video data to destination device 14 via computer readable medium 16 . Source device 12 and destination device 14 include desktop computers, notebook (eg, laptop) computers, tablet computers, set-top boxes, telephone handsets such as so-called “smart” phones, so-called “smart” phones. "can include any of a wide variety of devices, including pads, televisions, cameras, display devices, digital media players, video game consoles, video streaming devices, and the like. In some cases, source device 12 and destination device 14 may be equipped for wireless communication.

Destination device 14 may receive encoded video data to be decoded via computer readable medium 16 . Computer-readable medium 16 may include any tangible medium or device capable of moving encoded video data from source device 12 to destination device 14 . In one example, computer-readable medium 16 may comprise a communication medium that enables source device 12 to transmit encoded video data directly to destination device 14 in real-time. The encoded video data may be modulated according to a communication standard such as a wireless communication protocol and transmitted to the destination device 14 . Communication media may include any wireless or wired communication media, such as a radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium may form part of a packet-based network, such as a local area network, a wide area network, or a global network such as the Internet. Communication media may include routers, switches, base stations, or any other equipment that may be useful in facilitating communication from source device 12 to destination device 14 .

In some examples, encoded data may be output from output interface 22 to a storage device. Similarly, encoded data can be accessed from a storage device by an input interface. A storage device may include a hard drive, Blu-ray Discs, Digital Video Disc (DVD), Compact Disc Read-Only Memories (CD-ROMs), flash memory, volatile or non-volatile memory, or for storing encoded video data. may include any of a variety of distributed or locally accessible data storage media, such as any other suitable digital storage media for In a further example, the storage device may correspond to a file server or other intermediate storage device capable of storing the encoded video generated by the source device 12 . The destination device 14 may access the stored video data from the storage device via streaming or download. The file server may be any type of server capable of storing encoded video data and transmitting the encoded video data to the destination device 14 . Exemplary file servers include a web server (eg, for a web site), a file transfer protocol (FTP) server, Network Attached Storage (NAS) devices, or a local disk drive. Destination device 14 may access the encoded video data via any standard data connection, including an Internet connection. This may be a wireless channel (eg, Wi-Fi connection), a wired connection (eg, digital subscriber line (DSL), cable modem, etc.), or any combination thereof suitable for accessing encoded video data stored on a file server. may be included. The transmission of the encoded video data from the storage device may be a streaming transmission, a download transmission, or a combination thereof.

The techniques of this disclosure are not necessarily limited to wireless applications or environments. The techniques are applicable to over-the-air television broadcasts, cable television transmissions, satellite television transmissions, Internet streaming video transmissions such as dynamic adaptive streaming over http (DASH), digital encoded in a data storage medium. It can be applied to video coding to support any of a variety of multimedia applications, such as video, decoding of digital video stored on data storage media, or other applications. In some examples, coding system 10 may be configured to support one-way or two-way video transmission to support applications such as video streaming, video playback, video broadcasting, and/or video telephony.

In the example of FIG. 1 , source device 12 includes a video source 18 , a video encoder 20 , and an output interface 22 . The destination device 14 includes an input interface 28 , a video decoder 30 , and a display device 32 . According to this disclosure, video encoder 20 of source device 12 and/or video decoder 30 of destination device 14 may be configured to apply techniques for video coding. In other examples, the source device and destination device may include other components or configurations. For example, source device 12 may receive video data from an external video source, such as an external camera. Likewise, destination device 14 may interface with an external display device, but not include an integrated display device.

The illustrated coding system 10 of FIG. 1 is only one example. Techniques for video coding may be performed by any digital video encoding and/or decoding device. Although the techniques of this disclosure are generally performed by a video coding device, the techniques may be performed by a video encoder/decoder, typically referred to as a “CODEC”. Moreover, the techniques of this disclosure may also be performed by a video preprocessor. The video encoder and/or decoder may be a graphics processing unit (GPU) or similar device.

Source device 12 and destination device 14 are merely examples of such coding devices in which source device 12 generates coded video data for transmission to destination device 14 . In some examples, source device 12 and destination device 14 may operate in a substantially symmetrical manner such that source and destination devices 12 , 14 each include video encoding and decoding components. Accordingly, coding system 10 may support one-way or two-way video transmission between video devices 12 , 14 , for example, for video streaming, video playback, video broadcasting, or video telephony.

The video source 18 of the source device 12 may include a video capture device, such as a video camera, a video archive containing previously captured video, and/or a video feed interface that receives video from a video content provider. have. As a further alternative, video source 18 may generate computer graphics-based data as the source video, or a combination of live video, archived video, and computer-generated video.

In some cases, when video source 18 is a video camera, source device 12 and destination device 14 may form so-called camera phones or video phones. As mentioned above, however, the techniques described in this disclosure may be applied to video coding in general, and may be applied to wireless and/or wired applications. In each case, the captured, pre-captured, or computer-generated video may be encoded by the video encoder 20 . The encoded video information may then be output to a computer-readable medium 16 by an output interface 22 .

The computer-readable medium 16 is a transitory medium such as a wireless broadcast or wired network transmission, or a storage medium such as a hard disk, flash drive, compact disk, digital video disk, Blu-ray disk, etc. (ie, non-transitory storage medium). ), or other computer readable media. In some examples, a network server (not shown) may receive the encoded video data from the source device 12 and provide the encoded video data to the destination device 14, for example via a network transmission. Similarly, a computing device of a media production facility, such as a disk stamping facility, may receive encoded video data from source device 12 and generate a disk comprising the encoded video data. Accordingly, computer readable media 16 may be understood to include one or more computer readable media in various forms in various instances.

The input interface 28 of the destination device 14 receives information from the computer readable medium 16 . The information in the computer readable medium 16 is defined by the video encoder 20 and also used by the video decoder 30 , and may include syntax information in blocks and other coded units. , for example, including syntax elements describing characteristics and/or processing of a group of pictures (GOP). The display device 32 displays the decoded video data to a user, and can be configured to be any display device, such as a cathode ray tube (CRT), liquid crystal display (LCD), plasma display, organic light emitting diode (OLED) display, or other type of display device. It may include various display devices.

The video encoder 20 and the video decoder 30 may operate according to a video coding standard such as the High Efficiency Video Coding (HEVC) standard currently under development, and may follow the HEVC Test Model (HM). . As an alternative, the video encoder 20 and the video decoder 30 are configured by an International Telecommunications Union Telecommunication Standardization Sector (ITU-T), alternatively referred to as Moving Picture Expert Group (MPEG)-4 Part 10, Advanced Video Coding (AVC). It may operate according to other proprietary or industry standards, such as the H.264 standard, H.265/HEVC, or extensions of these standards. However, the techniques of this disclosure are not limited to any particular coding standard. Other examples of video coding standards include MPEG-2 and ITU-T H.263. Although not shown in FIG. 1 , in some aspects, each of the video encoder 20 and video decoder 30 may be integrated with an audio encoder and decoder, and both audio and video in a common data stream or in separate data streams. It may include suitable multiplexer-demultiplexer (MUX-DEMUX) units, or other hardware and software, to handle the encoding of both. If applicable, MUX-DEMUX units may conform to the ITU H.223 multiplexer protocol, or other protocols such as the User Datagram Protocol (UDP).

Each of the video encoder 20 and video decoder 30 includes one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, software, hardware , firmware, or any combinations thereof, or the like, as any of a variety of suitable encoder circuitry. When the techniques are implemented in part in software, the device may store the instructions for the software in a suitable non-transitory computer readable medium and execute the instructions in hardware using one or more processors to perform the techniques of this disclosure. . Each of video encoder 20 and video decoder 30 may be included in one or more encoders or decoders, either of which may be integrated as part of a combined encoder/decoder (CODEC) in a respective device. Devices including video encoder 20 and/or video decoder 30 may include integrated circuits, microprocessors, and/or wireless communication devices such as cellular telephones.

2 is a block diagram illustrating an example of a video encoder 20 that may implement video coding techniques. Video encoder 20 may perform intra-coding and inter-coding of video blocks within video slices. Intra coding relies on spatial prediction to reduce or remove spatial redundancy within a given video frame or picture of video. Inter-coding relies on temporal prediction to reduce or remove temporal redundancy within adjacent frames or pictures of a video sequence of video. Intra mode (I mode) may refer to any of several spatial-based coding modes. Inter-modes, such as unidirectional (aka, uni-prediction) prediction (P mode) or bi-prediction (aka, bi-prediction) (B mode), may refer to any of several temporal-based coding modes.

As shown in FIG. 2 , video encoder 20 receives a current video block within video frames to be encoded. In the example of FIG. 2 , the video encoder 20 includes a mode selection unit 40 , a reference frame memory 64 , a summer 50 , a transform processing unit 52 , a quantization unit 54 , and an entropy coding unit. (56). The mode selection unit 40 includes, in turn, a motion compensation unit 44 , a motion estimation unit 42 , an intra prediction (aka intra prediction) unit 46 , and a dividing unit 48 . For video block reconstruction, the video encoder 20 also includes an inverse quantization unit 58 , an inverse transform unit 60 , and a summer 62 . A deblocking filter (not shown in FIG. 2 ) may also be included to filter block boundaries to remove blockiness artifacts from the reconstructed video. If desired, a deblocking filter will typically filter the output of summer 62 . Additional filters (loop or post loop) may be used in addition to the deblocking filter. These filters are not shown for brevity, but if desired, the output of summer 50 may be filtered (as an in-loop filter).

During the encoding process, video encoder 20 receives a video frame or slice to be coded. A frame or slice may be divided into a plurality of video blocks. Motion estimation unit 42 and motion compensation unit 44 perform inter-prediction coding of a received video block with respect to one or more blocks within one or more reference frames to provide temporal prediction. Intra prediction unit 46 may alternatively provide spatial prediction by performing intra prediction coding of the received video block with respect to one or more neighboring blocks within the same frame or slice as the block to be coded. Video encoder 20 may, for example, perform multiple coding passes to select an appropriate coding mode for each block of video data.

Moreover, partitioning unit 48 may partition blocks of video data into subblocks based on evaluation of previous partitioning schemes in previous coding passes. For example, partitioning unit 48 initially partitions a frame or slice into largest coding units (LCUs), and divides each LCU into subcoding units based on rate-distortion analysis (eg, rate-distortion optimization). (sub-CUs). The mode selection unit 40 may further generate a quad tree data structure indicating dividing the LCU into sub-CUs. Leaf node CUs of a quad tree may include one or more prediction units (PUs) and one or more transform units (TUs).

This disclosure provides similar data structures (eg macroblocks and their subblocks in H.264/AVC) in the context of any of CU, PU, or TU in the context of HEVC, or other standards. The term “block” is used to refer to it. A CU includes a coding node, PUs, and TUs associated with the coding node. The size of the CU corresponds to the size of the coding node and is square in shape. The size of the CU may range from 8x8 pixels to the maximum size of a treeblock of 64x64 pixels or more. Each CU may include one or more PUs and one or more TUs. Syntax data associated with a CU may describe, for example, splitting the CU into one or more PUs. The splitting modes may differ depending on whether the CU is skip or direct mode encoded, intra prediction mode encoded, or inter prediction (aka inter prediction) mode encoded. PUs may be divided into non-square shapes. Syntax data associated with a CU may also describe partitioning the CU into one or more TUs, eg, according to a quad tree. A TU may be square or non-square (eg, rectangular) shaped.

The mode selection unit 40 may, for example, select one of the intra or inter coding modes based on the error result, and provide the resultant intra or inter coded block to the summer 50 to generate residual block data and It can be provided to summer 62 to reconstruct the encoded block for use as a reference frame. The mode selection unit 40 also provides syntax elements such as motion vectors, intra mode indicators, partition information, and other such syntax information to the entropy coding unit 56 .

Motion estimation unit 42 and motion compensation unit 44 may be highly integrated, but are illustrated separately for conceptual purposes. Motion estimation performed by motion estimation unit 42 is the process of generating motion vectors that estimate motion for video blocks. A motion vector is, for example, a video block within a current video frame or picture with respect to a predictive block (or other coded unit) within a reference frame with respect to the current block (or other coded unit) being coded within the current frame. may represent the displacement of PU of . A predictive block is a block to be coded, in terms of pixel difference, which may be determined by a sum of absolute difference (SAD), sum of square difference (SSD), or other difference metric. Blocks found to match closely with . In some examples, video encoder 20 can calculate values for sub-integer pixel positions of reference pictures stored in reference frame memory 64 . For example, video encoder 20 can interpolate values of quarter pixel positions, 1/8 pixel positions, or other partial pixel positions of a reference picture. Accordingly, the motion estimation unit 42 can perform a motion search with respect to full pixel positions and partial pixel positions and output a motion vector with partial pixel precision.

The motion estimation unit 42 calculates a motion vector for a PU of a video block in an inter-coded slice by comparing the position of the PU with the position of a predictive block of a reference picture. The reference picture may be selected from a first reference picture list (List 0) or a second reference picture list (List 1), each of which identifies one or more reference pictures stored in the reference frame memory 64 . The motion estimation unit 42 transmits the calculated motion vector to the entropy encoding unit 56 and the motion compensation unit 44 .

Motion compensation performed by the motion compensation unit 44 may include fetching or generating a predictive block based on the motion vector determined by the motion estimation unit 42 . Once again, motion estimation unit 42 and motion compensation unit 44 may, in some examples, be functionally integrated. Upon receiving the motion vector for the PU of the current video block, the motion compensation unit 44 may locate the predictive block pointed to by the motion vector in one of the reference picture lists. Summer 50 forms a residual video block by subtracting pixel values of the predictive block from pixel values of the current video block being coded, forming pixel difference values, as discussed below. In general, the motion estimation unit 42 performs motion estimation on the luma components, and the motion compensation unit 44 calculates the motion vectors calculated based on the luma components for both the chroma components and the luma components. use it Mode selection unit 40 may also generate the video blocks and syntax elements associated with the video slice for use by video decoder 30 when decoding video blocks of the video slice.

The intra prediction unit 46 may intra-predict the current block as an alternative to the inter prediction performed by the motion estimation unit 42 and the motion compensation unit 44 , as described above. In particular, intra prediction unit 46 may determine an intra prediction mode to use for encoding the current block. In some examples, intra prediction unit 46 may encode a current block using various intra prediction modes, eg, during separate encoding passes, and intra prediction unit 46 (or In some examples, the mode selection unit 40 may select an appropriate intra prediction mode to use from the tested modes.

For example, the intra prediction unit 46 may calculate rate distortion values using rate distortion analysis for various tested intra prediction modes, and select an intra prediction mode having the best rate distortion characteristic among the tested modes. can Rate-distortion analysis, in general, determines the amount of distortion (or error) between an encoded block and the original unencoded block that was encoded to produce the encoded block, as well as the amount of distortion (or error) used to generate the encoded block. Determines the bit rate (ie, number of bits). Intra prediction unit 46 may calculate a ratio from the distortions and rates for the various encoded blocks to determine which intra prediction mode shows the best rate distortion value for the block.

In addition, intra prediction unit 46 may be configured to code the depth blocks of the depth map using a depth modeling mode (DMM). Mode selection unit 40 may determine whether an available DMM mode produces better coding results than an intra prediction mode and other DMM modes using, for example, rate distortion optimization (RDO). Data for the texture image corresponding to the depth map may be stored in the reference frame memory 64 . The motion estimation unit 42 and the motion compensation unit 44 may also be configured to inter-predict the depth block of the depth map.

After selecting an intra prediction mode (e.g., a conventional intra prediction mode, or one of the DMM modes) for the block, intra prediction unit 46 sends information indicating the selected intra prediction mode for the block to an entropy coding unit ( 56) can be provided. Entropy coding unit 56 may encode information indicating the selected intra prediction mode. Video encoder 20 provides a plurality of intra prediction mode index tables and a plurality of modified intra prediction mode index tables (also referred to as codeword mapping tables), definitions of encoding contexts for various blocks, and a most probable intra prediction In the transmitted bitstream configuration data, which may include indications for the mode, may include an intra prediction mode index table, and a modified intra prediction mode index table to use for each of the contexts.

The video encoder 20 forms a residual video block by subtracting the prediction data from the mode selection unit 40 from the original video block being coded. Summer 50 represents the component or components that perform this subtraction operation.

Transform processing unit 52 applies a transform, such as a discrete cosine transform (DCT) or a conceptually similar transform, to the residual block to generate a video block including residual transform coefficient values. The transform processing unit 52 may perform other transforms that are conceptually similar to DCT. Wavelet transforms, integer transforms, subband transforms or other types of transforms may also be used.

Transform processing unit 52 applies the transform to the residual block, producing a block of residual transform coefficients. The transform may transform the residual information from a pixel value domain to a transform domain, such as a frequency domain. The transform processing unit 52 may send the resulting transform coefficients to the quantization unit 54 . The quantization unit 54 quantizes the transform coefficients to further reduce the bit rate. The quantization process may reduce the bit depth associated with some or all of the coefficients. The degree of quantization may be modified by adjusting the quantization parameter. In some examples, quantization unit 54 may then perform a scan of the matrix including the quantized transform coefficients. Alternatively, entropy encoding unit 56 may perform a scan.

After quantization, entropy coding unit 56 entropy codes the quantized transform coefficients. For example, entropy coding unit 56 may be configured for context adaptive variable length coding (CAVLC), context adaptive binary arithmetic coding (CABAC), syntax-based context adaptation Syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or other entropy coding techniques may be performed. In the case of context-based entropy coding, the context may be based on neighboring blocks. Following entropy coding by entropy coding unit 56 , the encoded bitstream may be transmitted to another device (eg, video decoder 30 ) or archived for later transmission or retrieval.

Inverse quantization unit 58 and inverse transform unit 60 apply inverse quantization and inverse transform, respectively, to reconstruct the residual block in the pixel domain, for example, for later use as a reference block. The motion compensation unit 44 may calculate a reference block by adding a residual block to a prediction block of one of the frames of the reference frame memory 64 . Motion compensation unit 44 may also apply one or more interpolation filters to the reconstructed residual block to calculate sub-integer pixel values for use in motion estimation. Summer 62 adds the reconstructed residual block to the motion compensated prediction block generated by motion compensation unit 44 to generate a reconstructed video block for storage in reference frame memory 64 . The reconstructed video block may be used as a reference block by the motion estimation unit 42 and the motion compensation unit 44 to inter-code a block within a subsequent video frame.

3 is a block diagram illustrating an example of a video decoder 30 that may implement video coding techniques. In the example of FIG. 3 , the video decoder 30 includes an entropy decoding unit 70 , a motion compensation unit 72 , an intra prediction unit 74 , an inverse quantization unit 76 , an inverse transform unit 78 , a reference frame a memory 82 , and a summer 80 . Video decoder 30 may, in some examples, perform a decoding pass generally inversely related to the encoding pass described with respect to video encoder 20 ( FIG. 2 ). The motion compensation unit 72 may generate prediction data based on the motion vectors received from the entropy decoding unit 70 , while the intra prediction unit 74 receives the intra prediction mode received from the entropy decoding unit 70 . Predictive data may be generated based on the indicators.

During the decoding process, video decoder 30 receives from video encoder 20 an encoded video bitstream representing video blocks of an encoded video slice and associated syntax elements. Entropy decoding unit 70 of video decoder 30 entropy decodes the bitstream to generate quantized coefficients, motion vectors or intra prediction mode indicators, and other syntax elements. Entropy decoding unit 70 forwards motion vectors and other syntax elements to motion compensation unit 72 . Video decoder 30 may receive syntax elements at a video slice level and/or a video block level.

When a video slice is coded as an intra-coded (I) slice, intra-prediction unit 74 is configured to determine the size of the current video slice based on the signaled intra prediction mode and data from previously decoded blocks of the current frame or picture. Predictive data for video blocks may be generated. When a video frame is coded as an inter-coded (eg, B, P or GPB) slice, motion compensation unit 72 based on motion vectors and other syntax elements received from entropy decoding unit 70 . to generate prediction blocks for the video block of the current video slice. Predictive blocks may be generated from one of the reference pictures in one of the reference picture lists. The video decoder 30 may construct the reference frame lists, List 0 and List 1 , using default construction techniques based on the reference pictures stored in the reference frame memory 82 .

Motion compensation unit 72 determines prediction information for a video block of a current video slice by parsing motion vectors and other syntax elements, and uses the prediction information to generate predictive blocks for the current video block being decoded. For example, motion compensation unit 72 uses some of the received syntax elements to determine the prediction mode (eg, intra or inter prediction) used to code the video blocks of the video slice, the inter prediction slice type ( For example, B slice, P slice, or GPB slice), configuration information for one or more of the reference picture lists for the slice, motion vectors for each inter-encoded video block of the slice, each inter-coding of the slice determine the inter prediction state for the video block that has been used, and other information for decoding the video blocks in the current video slice.

Motion compensation unit 72 may also perform interpolation based on interpolation filters. Motion compensation unit 72 may use interpolation filters used by video encoder 20 during encoding of video blocks to calculate interpolated values for sub-integer pixels of reference blocks. In this case, motion compensation unit 72 may determine interpolation filters used by video encoder 20 from the received syntax elements and generate a predictive block using the interpolation filters.

Data for the texture image corresponding to the depth map may be stored in the reference frame memory 82 . Motion compensation unit 72 may also be configured to inter-predict depth blocks of the depth map.

Image and video compression suffered rapidly, leading to various coding standards. These video coding standards are ITU-T H.261, ISO/IEC MPEG-1 Part 2, ITU-T H.262 or ISO/IEC MPEG-2 Part 2, ITU-T H.263, ISO/IEC MPEG- Advanced Video Coding (AVC), also known as 4 Part 2, ITU-T H.264 or ISO/IEC MPEG-4 Part 10, and High Efficiency Video Coding (HEVC), also known as ITU-T H.265 or MPEG-H Part 2 includes AVC includes extensions such as Scalable Video Coding (SVC), Multiview Video Coding (MVC) and Multiview Video Coding plus Depth (MVC+D), and 3D-AVC (3D-AVC). HEVC includes extensions such as Scalable HEVC (SHVC), Multiview HEVC (MV-HEVC), and 3D HEVC (3D-HEVC).

There is also a new video coding standard called Versatile Video Coding (VVC) that is being developed by the Joint Video Expert Team (JVET) of ITU-T and ISO/IEC. VVC's latest Working Draft (WD) is included in JVET-L1001-v5 publicly available at http://phenix.it-sudparis.eu/jvet/doc_end_user/documents/12_Macao/wg11/JVET-L1001-v11.zip has been

Intra Random Access Point (IRAP) pictures and leading pictures are discussed.

In HEVC, the following pictures are considered as Intra Random Access Point (IRAP) pictures: IDR, BLA, and CRA pictures. In the case of VVC, during the 12th JVET meeting in October 2018, it was agreed to have both IDR and CRA pictures as IRAP pictures.

IRAP pictures provide two important functions/benefits: First, the presence of an IRAP picture indicates that the decoding process can start from that picture. This function allows for a random access feature where the decoding process starts at a given position in the bitstream, as long as the IRAP picture is there, without necessarily being at the beginning of the bitstream. Second, the presence of an IRAP picture refreshes the decoding process so that, except for Random Access Skipped Leading (RASL) pictures, the coded picture that begins the IRAP picture is coded without any reference to previous pictures. As a result, the presence of an IRAP picture in the bitstream will stop propagating to the IRAP picture and to the picture following the IRAP picture in decoding order, any errors that may occur while decoding the picture coded before that IRAP picture. .

IRAP pictures provide important functions, but come with a penalty for compression efficiency. The presence of IRAP pictures will cause a spike in bitrate. This penalty for compression efficiency is due to two reasons: first, since an IRAP picture is an intra-predicted picture, the picture itself requires relatively more bits for representation compared to other pictures that are inter-predicted pictures; Second, since the presence of IRAP pictures will break temporal prediction (this is because the decoder refreshes the decoding process, and one of the operations of the decoding process for this will remove old reference pictures from the DPB), they It will have fewer reference pictures for predictive coding, thus making the coding of pictures that follow the IRAP picture in decoding order less efficient (ie, require more bits for representation).

Among the picture types considered as IRAP pictures, the IDR picture in HEVC has different signaling and derivation compared to other picture types. Some of the differences are:

- For signaling and derivation of the POC value of the IDR picture, the most significant bit (MSB) portion of the POC is not derived from the previous key picture and is simply set to zero.

- In the case of signaling information necessary for reference picture management, the slice header of the IDR picture does not include information that needs to be signaled to assist reference picture management. For other picture types (ie, CRA, Trailing, Temporal Sublayer Access (TSA), etc.), a reference picture set (RPS) described in the section below or other forms of similar information (eg, reference information such as picture lists) is required for the reference picture marking process (ie, the process of determining the status of reference pictures in the DPB that is used for reference or not used for reference). However, in the case of an IDR picture, this information does not need to be signaled because the presence of the IDR indicates that the decoding process should simply mark all reference pictures of the DPB as unused for reference.

In addition to the IRAP picture concept, there are also leading pictures associated with the IRAP picture, if present. Leading pictures are pictures that follow the associated IRAP picture in decoding order but precede the IRAP picture in output order. According to the coding scheme and the picture reference structure, the leading pictures are further identified into two types. The first type are leading pictures that may not be decoded correctly if the decoding process starts at the associated IRAP picture. This may occur because these leading pictures are coded with reference to pictures that precede the IRAP picture in decoding order. These leading pictures are called random access skipped leading (RASL). The second type are leading pictures that must be decoded correctly even if the decoding process starts with the associated IRAP picture. This is possible because these leading pictures are coded without direct or indirect reference to the pictures preceding the IRAP picture in decoding order. These leading pictures are called random access decodable leading (RADL). In HEVC, when there are RASL and RADL pictures, for RASL and RADL pictures associated with the same IRAP picture, there is a constraint that RASL pictures must precede RADL pictures in output order.

In HEVC and VVC, since IRAP pictures and leading pictures are given different NAL unit types, they can be easily identified by system level applications. For example, a video splicer identifies IRAP pictures, particularly from non-IRAP pictures, and from trailing pictures, coded bits to identify leading pictures, including determination of RASL and RADL pictures. There is a need to understand the coded picture types without understanding too many details of the syntax element in the stream. Trailing pictures are pictures that are associated with the IRAP picture and follow the IRAP picture in output order. A picture associated with a particular IRAP picture is a picture that follows the particular IRAP picture in decoding order and precedes any other IRAP picture in decoding order. To this end, providing IRAP and leading pictures with their own NAL unit type is helpful in this application.

For HEVC, NAL unit types for IRAP pictures include:

- BLA with a leading picture (BLA_W_LP): NAL unit of a BLA (Broken Link Access) picture that can be followed by one or more leading pictures in decoding order.

- BLA with RADL (BLA_W_RADL): A NAL unit of a BLA picture that may be followed by one or more RADL pictures in decoding order but no RASL pictures.

- BLA without a leading picture (BLA_N_LP): NAL unit of a BLA picture not followed by a leading picture in decoding order.

- IDR with RADL (IDR_W_RADL): A NAL unit of an IDR picture that may be followed by one or more RADL pictures in decoding order but no RASL pictures.

- IDR without a leading picture (IDR_N_LP): NAL unit of an IDR picture not followed by a leading picture in decoding order.

- CRA: NAL unit of a clean random access (CRA) picture that can be followed by leading pictures (ie, RASL picture or RADL picture or both).

- RADL: NAL unit of RADL picture.

- RASL: NAL unit of RASL picture.

In the case of VVC, according to the description of this document, the NAL unit type for IRAP pictures and leading pictures is still not clear / yet not determined.

File format standards are discussed.

The file format standards are ISO Base Media File Format (ISOBMFF, ISO/IEC 14496-12, hereinafter "ISO/IEC 14996-12"), and MPEG-4 File Format (ISO/IEC 14496-14), 3GPP File Format ( 3GPP TS 26.244), and other file format standards derived from ISOBMFF, including the AVC file format (ISO/IEC 14496-15, hereinafter "ISO/IEC 14996-15"). Therefore, ISO/IEC 14496-12 specifies the ISO base media file format. Other documents extend the ISO base media file format for specific applications. For example, ISO/IEC 14496-15 describes the carriage of NAL unit structured video in the ISO base media file format. H.264/AVC and HEVC as well as their extensions are examples of NAL unit structured video. ISO/IEC 14496-15 contains sections describing carriage of H.264/AVC NAL units. Additionally, section 8 of ISO/IEC 14496-15 describes a carriage of HEVC NAL units. Therefore, it can be said that section 8 of ISO/IEC 14496-15 describes the HEVC file format.

ISOBMFF is used as the basis for many codec encapsulation formats, such as the AVC file format, as well as many multimedia container formats, such as the MPEG-4 file format, the 3GPP file format (3GP) and the DVB file format. In addition to continuous media such as audio and video, metadata, as well as static media such as images, can be stored in files that comply with ISOBMFF. Files structured according to ISOBMFF include segments for local media file playback, progressive download of remote files, Dynamic Adaptive Streaming over HTTP (DASH), containers for content to be streamed and its packetization instructions, real-time media stream received It can be used for many purposes, including the recording of Thus, although originally designed for storage, ISOBMFF has proven valuable for streaming, eg progressive download or DASH. For streaming purposes, movie fragments defined in ISOBMFF may be used. In addition to continuous media such as audio and video, metadata, as well as static media such as images, can be stored in files that comply with ISOBMFF.

A file conforming to the HEVC file format may contain a series of objects known as boxes. A box may be an object-oriented building block defined by a unique type identifier and length. A box is the basic syntax structure of ISOBMFF and may contain a 4-character coded box type, the number of bytes in the box, and a payload. That is, the box may be a syntax structure including a coded box type, the number of bytes in the box, and a payload. In some cases, all data of a file that conforms to the HEVC file format may be contained within boxes and files that are not within boxes may have no data. Thus, an ISOBMFF file may consist of a sequence of boxes, and boxes may contain other boxes. For example, the payload of a box may include one or more additional boxes.

Files compliant with ISOBMFF may contain different types of boxes. For example, a file conforming to ISOBMFF may include a file type box, a media data box, a movie box, a movie short box, and the like. In this example, the file type box contains file type and compatibility information. A media data box may contain samples (eg, coded pictures). A movie box (“moov”) contains metadata for the continuous media streams present in the file. Each of the successive media streams may be represented as a track in a file. For example, a movie box may contain metadata about the movie (eg, logical and timing relationships between samples, and also pointers to locations of the samples). A movie box may include several types of subboxes. Subboxes of a movie box may contain one or more track boxes. The track box may contain information about individual tracks of the movie. The track box may include a track header box specifying the full information of a single track. Also, the track box may include a media box including a media information box. The media information box may include a sample table box containing data indexing media samples in the track. The information in the Sample Table box can be used to locate samples in time and, for each of the samples in the track, the type, size, container, and offset of the sample into that container. Thus, metadata for a track is contained in a track box (“trak”), whereas the media content of a track is contained in a media data box (“mdat”) or directly in a separate file. Media content for tracks includes or consists of a sequence of samples, such as audio or video access units.

ISOBMFF specifies the following types of tracks: a media track containing the base media stream, a hint track containing media transport instructions or representing a received packet stream, and a timed metadata track containing time-synchronized metadata . The metadata for each track contains a list of sample description entries, each providing the coding or encapsulation format used for the track and initialization data used to process the format. Each sample is associated with one of the track's sample description entries.

ISOBMFF makes it possible to specify sample-specific metadata with a variety of mechanisms. Specific boxes within the sample table box (“stbl”) have been standardized to respond to a general need. The Sample Table box contains a sample table containing all time and data indexing of the media samples in the track. Tables in the Sample Table box can be used to locate samples in time, determine their type (eg, whether I-frames), and determine their size, container, and offset into that container.

The Movie Short Box is the top level box. Each movie short box provides information that was previously in the movie box. A short movie box may include one or more track fragments (“traf”) boxes. Within a movie snippet, there is a set of zero or more track snippets per track. A track fragment in turn contains zero or more track runs, each documenting successive runs of samples over that track. For example, each track run may include samples of successive pictures in some order, such as decoding order. The Track Fragments box is defined in the 14996-12 specification and contains metadata for one or more track fragments. For example, a track fragment box may include a track fragment header box indicating a track identifier (ID), base data offset, sample description index, default sample duration, default sample size, and default sample flags. A track fragment box may include one or more track fragment travel boxes, each documenting a contiguous set of samples for a track. For example, a track fragment box may contain syntax elements indicating number of samples, data offset, sample flags, sample duration, sample size, sample construction time offset, and the like. Within these structures, many fields are optional and can be defaulted.

Stream Access Point (SAP) is discussed.

The ISO Media File Format (ISOBMFF) defines the concept of a so-called Stream Access Point (SAP). SAP enables random access to the container of the media stream(s). A container may contain more than one media stream, each being an encoded version of a contiguous media of a given media type. SAP refers to a location within a container where playback of an identified media stream is initiated from (a) the information contained in the container and (b) available externally or from other part(s) of the container starting from that location. This is a location that allows you to start using only data. The derived specification should specify whether initialization data is needed to access the container in SAP and how the initialization data can be accessed.

There are six types of SAP defined, these are:

Type 1 corresponds to what is known as a "closed GoP random access point" in some coding schemes (starting from improved sample-based angular intra prediction (ISAP), and in decoding order all access units are can be decoded correctly, resulting in a continuous time sequence of correctly decoded access units without gaps), in addition, an access unit in decoding order is also the first access unit in construction order.

Type 2 corresponds to what is known as a “closed GoP random access point” in some coding schemes, in which case the first access unit in decoding order in the media stream is not the first access unit in construction order.

Type 3 corresponds to what is known as an "open GoP random access point" in some coding schemes, where in decoding order there are some access units that follow a random access point that cannot be decoded correctly and the random access point access unit is in the construction order It may not be the first access unit.

Type 4 corresponds to what is known as a "Gradual Decoding Refresh (GDR) starting point" in some coding schemes.

Type 5 corresponds to the case where there is at least one access unit that cannot be decoded correctly and has a presentation time greater than TDEC, starting with the first access unit for decoding in decoding order, where TDEC is the first access unit for decoding The earliest presentation time of any access unit, starting from the access unit.

Type 6 corresponds to the case where there is at least one access unit that cannot be decoded correctly and has a presentation time greater than TDEC, starting with the first access unit for decoding in decoding order, where TDEC is the first access unit for decoding Starting from the access unit, it is not the earliest presentation time of any access unit.

In the case of HEVC, the design of NAL unit types for IRAP pictures was made using one of the goals of easy mapping between IRAP types and SAP types, especially SAP types 1-3.

Dynamic Adaptive Streaming (DASH) over HTTP is discussed.

Dynamic adaptive streaming over HTTP (DASH) specified in ISO/IEC 23009-1 is a standard for HTTP (adaptive) streaming applications. DASH mainly specifies the format of a Media Presentation Description (MDP), also known as a manifest, and a media segment format. MPD describes the media available on the server and allows DASH clients to autonomously download media versions at the time of the media they are interested in.

DASH is based on a hierarchical data model. A presentation is described by an MPD document that describes a sequence of periods that make up a media presentation. A period typically represents a period of media content during which a consistent set of encoded versions of the media content is available, eg the set of available bitrates, languages, captions, subtitles, etc. does not change over a period of time. .

For a period of time, the material is arranged into fitting sets. A adaptation set represents a set of interchangeable encoded versions of one or several media content components. For example, there may be one set of adaptations for the main video component and a separate set of adaptations for the main audio component. Other available material, such as captions or audio descriptions, may each have a separate set of adaptations. The material may also be provided in multiplexed form, in which case the interchangeable versions of the multiplex will be described as a single adaptation set, for example a adaptation set containing both main audio and main video for a period of time. can Each of the multiplexed components may be individually described by a media content component description.

A fitting set includes a set of representations. A representation describes a deliverable encoded version of one or several media content components. A representation includes one or more media streams (one for each media content component in the multiplex). Any single representation in the adaptation set is sufficient to render the contained media content components. By collecting different representations in one adaptation set, the media presentation author expresses that the representations represent cognitively equivalent content. Typically, this means that clients can dynamically switch from representation to representation within an adaptation set to adapt to network conditions or other factors. Transition refers to the presentation of the decoded data up to a given time t, and the presentation of the decoded data in another representation after the time t. If representations are included in one adaptation set, and the client transitions appropriately, the media presentation is expected to be perceived smoothly throughout the transition. Clients may ignore representations that rely on codecs or other rendering technologies that they do not support or are otherwise unsuitable for. Within a presentation, content can be temporally divided into segments for proper accessibility and delivery. To access one segment, a URL for each segment is provided. Consequently, a segment is the largest data unit that can be retrieved in a single HTTP request.

A typical procedure for DASH-based HTTP streaming includes the following steps.

1) The client obtains the MPD of streaming content, eg a movie. The MPD contains information about different alternative representations, eg bit rate, video resolution, frame rate, audio language of streaming content, as well as URLs (initialization segment and media segments) of HTTP resources.

2) Based on the information in the MPD and the client's local information, e.g., network bandwidth, decoding/display capabilities, and user preferences, the client can select the desired representation(s), one segment (or part thereof) at a time. ) is requested.

3) When the client detects a change in network bandwidth, it requests segments of different representations with better matching bitrates, ideally starting with the segment starting at the random access point.

During an HTTP streaming "session", in response to a user request to navigate back to a past location or forward to a future location, the client requests past or future segments, starting with a segment close to the desired location and ideally starting at a random access point. A user may also request a fast forward progression of content, which may be realized by decoding only intra coded video pictures or by requesting enough data to decode only a temporal subset of the video stream.

The problems and leading pictures of the existing IRAP are discussed.

The current design of NAL unit types for leading pictures and IRAP pictures has the following problems:

- of leading pictures (i.e. RASL and RADL) at the NAL unit header level for the reason to help system level applications identify the RASL when decoding starts from their associated IRAP picture and remove it from the bitstream by simply parsing the NAL unit header There are two NAL unit types given for identification. However, in practice, such removal by system applications is seldom performed, the leading pictures and their associated IRAP picture are encapsulated in the same DASH media segment, and in HTTP-based adaptive streaming this DASH media segment is requested by the client. Therefore, the leading pictures and their associated IRAP picture are not separately requested so that the request of RASL pictures can be avoided. Moreover, allowing system applications to remove or not remove RASL pictures, consequently requires a video coding specification to address both possibilities, with or without RASL pictures, and two alternative hypothetical (HRD) decoder reference) requires the specification of the bitstream conformance for both situations, including the specification of the HRD containing the set of parameters.

- For IRAP pictures, several NAL unit types are given to distinguish them based on the presence of leading pictures for the purpose of easy mapping to SAP types 1-3. However, due to the flexibility of the definition of IRAP NAL unit types, especially CRA types, in many cases the mapping between IRAP picture types and SAP types cannot be achieved simply by knowing the NAL unit type. Access units following IRAP pictures still need to be checked. For example, a CRA may be followed by zero or more RASLs or zero or more RADLs, or none of these, and thus may be mapped as SAP type 1, type 2 or type 3. The only way to know how to map a CRA picture to an SAP type is to parse the access units that follow to see if there are leading pictures and then what type of leading pictures there are.

Video coding techniques are disclosed herein that constrain the set of NAL unit types available for video data to no more than 5 specific NAL unit types (eg, constrain the number of NAL unit types to 4). Each NAL unit has a header and is identified by an identifier (ID). Fewer NAL types mean that the ID can be smaller. Thus, the size of each NAL unit can be reduced, which significantly reduces the size of the bitstream (memory saving). It also reduces the size of each packet used to transmit the bitstream, thereby reducing network resource usage. Moreover, no more than 5 specific NAL unit types allow leading and trailing pictures (aka non-IRAP pictures) to share the same NAL unit type. This also allows NAL unit types to indicate whether an I-RAP picture is associated with a RADL picture and/or a RASL picture. Additionally, certain NAL unit types may be mapped to different SAP types in DASH. Video coding techniques for when non-IRAP pictures are not identified by NAL unit type are also disclosed herein. In this case, the flags in the bitstream are set to a specific value indicating whether the IRAP picture is associated with a RADL picture or a RASL picture.

4 is a schematic diagram of one embodiment of a video bitstream 400 . As used herein, video bitstream 400 may also refer to a coded video bitstream, a bitstream, or variants thereof. As shown in FIG. 4 , the bitstream 400 includes a sequence parameter set (SPS) 410 , a picture parameter set (PPS) 412 , a slice header 414 and an image. data 420 . In a practical application, the slice header 414 may be referred to as a tile group header.

The SPS 410 includes data common to all pictures in a sequence of pictures (SOP). In contrast, the PPS 412 contains data common to the entire picture. The slice header 414 includes information about the current slice, for example, the slice type, which of the reference pictures will be used, and the like. SPS 410 and PPS 412 may be generally referred to as parameter sets. SPS 410 , PPS 412 , and slice header 414 are types of Network Abstraction Layer (NAL) units. Image data 420 includes data associated with images or video being encoded or decoded. The image data 420 may simply be referred to as a payload or data carried in the bitstream 400 .

In one embodiment, SPS 410 , PPS 412 , slice header 414 , or another portion of bitstream 400 contains a plurality of reference picture list structures each including a plurality of reference picture entries. carry A person of ordinary skill in the art will understand that the bitstream 400 may include other parameters and information in practical applications.

5 is a representation 500 of the relationship between the I-RAP picture 502 with respect to leading pictures 504 and trailing pictures 506 in decoding order 508 and presentation order 510 . In one embodiment, the I-RAP picture 502 is referred to as a clean random access (CRA) picture or an instantaneous decoder refresh (IDR) picture with a RADL picture.

5, the leading pictures 504 (eg, pictures 2 and 3) follow the I-RAP picture 502 in decoding order 508, but I-RAP picture 502 in presentation order 510 - precedes the RAP picture 502 . Trailing picture 506 follows I-RAP picture 502 in both decoding order 508 and presentation order 510 . Although two leading pictures 504 and one trailing picture 506 are shown in FIG. 5 , those skilled in the art will find that in practical applications more or fewer leading pictures 504 and It will be appreciated that/or trailing pictures 506 may be in decoding order 508 and presentation order 510 .

The leading pictures 504 of FIG. 5 are divided into two types, namely, RASL and RADL. When decoding starts at the I-RAP picture 502 (eg, picture 1), the RADL picture (eg, picture 3) can be properly decoded; However, the RASL picture (eg, picture 2) cannot be decoded properly. Therefore, the RASL picture is discarded. Considering the distinction between RADL and RASL pictures, the type of the leading picture associated with the I-RAP picture should be identified as RADL or RASL for efficient and proper coding.

6 is one embodiment of a method 600 of encoding a video bitstream (eg, bitstream 400 ) implemented by a video encoder (eg, video encoder 20 ). This method 600 may be performed when a picture (eg, from a video) is encoded into a video bitstream and then transmitted towards a video decoder (eg, video decoder 30 ). This method 600 improves the encoding process (eg, because a limited set of NAL unit types that identify the type of the leading picture associated with the I-RAP picture are used (eg, the encoding process is compared to conventional encoding) making it more efficient and faster than processes, etc.). Thus, substantially, the performance of the codec is improved, leading to a better user experience.

At block 602, a set of less than five NAL unit types available for video data is stored in the memory of the video encoder. In one embodiment, a set of less than 5 NAL unit types is an intra random access point (IRAP) with leading and trailing pictures NAL unit type, random access skipping leading (RASL) NAL unit type, random access decodable Includes IRAP with leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. In one embodiment, the set of less than 5 NAL unit types is constrained to only these 4 NAL unit types. In one embodiment, both leading and trailing pictures (eg, leading pictures 504 and trailing pictures 506 ) are assigned a leading and trailing pictures NAL unit type.

At block 604 , a NAL unit type is selected from a set of less than five NAL unit types for a picture from the video data (eg, picture 2 or picture 3 in FIG. 5 ). For example, the NAL unit type for picture 2 of FIG. 5 may be IRAP with a RASL NAL unit type. As another example, the NAL unit type for picture 3 of picture 5 may be IRAP with a RADL NAL unit type.

In one embodiment, an IRAP with a RASL NAL unit type is selected for an IRAP picture that is followed by one or more RASL pictures and zero or more RADL pictures in decoding order. In one embodiment, an IRAP picture is referred to as a CRA picture. In one embodiment, an IRAP with a RASL NAL unit type is referred to as a Clean Random Access (CRA) NAL unit type. In one embodiment, an IRAP with a RASL NAL unit type is designated IRAP_W_RASL. In one embodiment, the IRAP_W_RASL designation corresponds to Stream Access Point (SAP) Type 3 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol.

In one embodiment, an IRAP with a RADL NAL unit type is selected for an IRAP picture followed by one or more RADL pictures and zero RADL pictures in decoding order. In one embodiment, an IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture. In one embodiment, an IRAP with a RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with a RADL NAL unit type. In one embodiment, an IRAP with a RADL NAL unit type is designated as IRAP_W_RADL. In one embodiment, IRAP_W_RADL corresponds to Stream Access Point (SAP) Type 2 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol.

In one embodiment, an IRAP without leading pictures NAL unit type is selected for an IRAP picture not followed by a leading picture in decoding order. In one embodiment, an IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture. In one embodiment, IRAP without leading pictures NAL unit type is referred to as instantaneous decoder refresh (IDR) without leading pictures NAL unit type. In one embodiment, IRAP without leading pictures NAL unit type is designated as IRAP_N_LP. In one embodiment, the IRAP_N_LP designation corresponds to Stream Access Point (SAP) Type 1 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol.

At block 606 , a video bitstream (eg, bitstream 400 of FIG. 4 ) is generated. The video bitstream includes an identifier that identifies the selected NAL unit type as well as the NAL unit corresponding to the selected NAL unit type. The identifier may be, for example, a flag or a number of bits.

At block 608 , the video encoder sends a video bitstream (eg, bitstream 400 ) towards a video decoder. A video bitstream may also be referred to as a coded video bitstream or an encoded video bitstream. Once received by the video decoder, the encoded video bitstream is decoded (eg, as described below) to display on an electronic device (eg, smart phone, tablet, laptop, personal computer, etc.) or Generate or create an image to be displayed to the user on the screen.

7 is one embodiment of a method 700 for decoding a coded video bitstream (eg, bitstream 400 ) implemented by a video decoder (eg, video decoder 30 ). The method 700 may be performed after the decoded bitstream is received directly or indirectly from a video encoder (eg, video encoder 20 ). This method 700 improves the decoding process (eg, because a limited set of NAL unit types that identify the type of the leading picture associated with the I-RAP picture are used (eg, the decoding process is compared to conventional decoding) making it more efficient and faster than processes, etc.). Thus, substantially, the performance of the codec is improved, leading to a better user experience.

At block 702, a set of less than five network abstraction layer (NAL) unit types available for video data is stored. In one embodiment, the set of less than 5 NAL unit types is: Intra Random Access Point (IRAP) with Leading and Trailing Pictures NAL Unit Type, Random Access Skip Type Leading (RASL) NAL Unit Type, Random Access Decodable Includes IRAP with leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. In one embodiment, the set of less than 5 NAL unit types is constrained to only these 4 NAL unit types. In one embodiment, both leading and trailing pictures (eg, leading pictures 504 and trailing pictures 506 ) are assigned a leading and trailing pictures NAL unit type.

At block 704 , a coded video bitstream (eg, bitstream 400 ) including a NAL unit and an identifier is received. At block 706 , the NAL unit type used to encode the NAL unit is determined based on the identifier from the set of less than 5 NAL unit types.

For example, the NAL unit type for picture 2 of FIG. 5 may be IRAP with a RASL NAL unit type. As another example, the NAL unit type for picture 3 of picture 5 may be IRAP with a RADL NAL unit type.

In one embodiment, an IRAP with a RASL NAL unit type is selected for an IRAP picture that is followed by one or more RASL pictures and zero or more RADL pictures in decoding order. In one embodiment, an IRAP picture is referred to as a CRA picture. In one embodiment, an IRAP with a RASL NAL unit type is referred to as a Clean Random Access (CRA) NAL unit type. In one embodiment, an IRAP with a RASL NAL unit type is designated IRAP_W_RASL. In one embodiment, the IRAP_W_RASL designation corresponds to Stream Access Point (SAP) Type 3 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol.

In one embodiment, an IRAP with a RADL NAL unit type is selected for an IRAP picture followed by one or more RADL pictures and zero RADL pictures in decoding order. In one embodiment, an IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture. In one embodiment, an IRAP with a RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with a RADL NAL unit type. In one embodiment, an IRAP with a RADL NAL unit type is designated as IRAP_W_RADL. In one embodiment, IRAP_W_RADL corresponds to Stream Access Point (SAP) Type 2 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol.

In one embodiment, an IRAP without leading pictures NAL unit type is selected for an IRAP picture not followed by a leading picture in decoding order. In one embodiment, an IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture. In one embodiment, IRAP without leading pictures NAL unit type is referred to as instantaneous decoder refresh (IDR) without leading pictures NAL unit type. In one embodiment, IRAP without leading pictures NAL unit type is designated as IRAP_N_LP. In one embodiment, the IRAP_N_LP designation corresponds to Stream Access Point (SAP) Type 1 in Dynamic Adaptive Streaming (DASH) over Hypertext Transfer Protocol.

At block 708 , a presentation order (eg, presentation order 510 in FIG. 5 ) for pictures included in the NAL unit is assigned based on the determined NAL unit type. The presentation sequence may be used to generate or generate an image for display to a user on a display or screen of an electronic device (eg, a smart phone, tablet, laptop, personal computer, etc.).

8 is one embodiment of a method 800 of encoding a video bitstream (eg, bitstream 400 ) implemented by a video encoder (eg, video encoder 20 ). This method 800 may be performed when a picture (eg, from a video) is encoded into a video bitstream and then transmitted towards a video decoder (eg, video decoder 30 ). This method 800 improves the encoding process because, for example, a flag is set to indicate that the NAL unit for a non-IRAP picture is either RADL or RASL (e.g., replacing the encoding process with conventional encoding processes). more efficient and faster, etc.). Thus, substantially, the performance of the codec is improved, leading to a better user experience.

At block 802 , a bitstream is generated that includes a NAL unit for a non-intra random access point (non-IRAP) picture associated with an intra random access point (IRAP) picture. The non-IRAP picture may be a leading picture (eg, leading picture 504) or a trailing picture (tailing picture 506).

At block 804 , a first flag in the bitstream is set to a first value indicating that the NAL unit for the non-IRAP picture contains a random access decodable leading (RADL) picture. In one embodiment, the first flag is designated as RadlPictureFlag and the second flag is designated as RaslPictureFlag. In one embodiment, the first value is one (1). In one embodiment, the first flag is set equal to the first value when the picture order count (POC) value of the non-IRAP picture is less than the POC value of the IRAP picture. In one embodiment, the first flag is a first value when each reference picture list for a non-IRAP picture contains no pictures other than an IRAP picture associated with a non-IRAP picture or another RADL picture associated with an IRAP picture. is set the same as

At block 806 , a second flag in the bitstream is set to a first value to indicate that the NAL unit for the non-IRAP picture includes a random access skipped leading (RASL) picture. In one embodiment, the second flag is set equal to the first value when the picture order count (POC) value of the non-IRAP picture is less than the POC value of the IRAP picture. In one embodiment, a second flag when the reference picture list for a non-IRAP picture includes at least one reference picture preceding an IRAP picture associated with the non-IRAP picture or another RASL picture associated with an IRAP picture in decoding order is set equal to the first value.

In one embodiment, the first flag and the second flag may be set to a second value to indicate that the NAL unit for the non-IRAP picture does not include a RADL picture or a RASL picture. In one embodiment, the second value is zero. In one embodiment, neither the first flag nor the second flag is set to a first value for a non-IRAP picture.

At block 808 , the video encoder sends a video bitstream (eg, bitstream 400 ) towards a video decoder. A video bitstream may also be referred to as a coded video bitstream or an encoded video bitstream. Once received by the video decoder, the encoded video bitstream is decoded (eg, as described below) to display on an electronic device (eg, smart phone, tablet, laptop, personal computer, etc.) or Generate or create an image to be displayed to the user on the screen.

9 is one embodiment of a method 900 for decoding a coded video bitstream (eg, bitstream 400 ) implemented by a video decoder (eg, video decoder 30 ). The method 900 may be performed after the decoded bitstream is received directly or indirectly from a video encoder (eg, video encoder 20 ). This method 900 improves the decoding process because, for example, a flag is set to indicate that the NAL unit for a non-IRAP picture is either RADL or RASL (e.g., comparing the decoding process to conventional decoding processes). more efficient and faster, etc.). Thus, substantially, the performance of the codec is improved, leading to a better user experience.

At block 902 , a coded video bitstream including a first flag, a second flag, and a NAL unit for a non-intra random access point (non-IRAP) picture associated with an intra random access point (IRAP) picture is received . The non-IRAP picture may be a leading picture (eg, leading picture 504) or a trailing picture (tailing picture 506).

At block 904 , a determination that the NAL unit for the non-IRAP picture includes a random access decodable leading (RADL) picture is made when a first flag in the bitstream is set to a first value. In one embodiment, the first flag is designated as RadlPictureFlag and the second flag is designated as RaslPictureFlag. In one embodiment, the first value is one (1). In one embodiment, the first flag is set equal to the first value when the picture order count (POC) value of the non-IRAP picture is less than the POC value of the IRAP picture. In one embodiment, the first flag is a first value when each reference picture list for a non-IRAP picture contains no pictures other than an IRAP picture associated with a non-IRAP picture or another RADL picture associated with an IRAP picture. is set the same as

At block 906 , a determination that the NAL unit for the non-IRAP picture includes a random access skip type leading (RASL) picture is made when a second flag in the bitstream is set to a first value. In one embodiment, the second flag is set equal to the first value when the picture order count (POC) value of the non-IRAP picture is less than the POC value of the IRAP picture. In one embodiment, a second flag when the reference picture list for a non-IRAP picture includes at least one reference picture preceding an IRAP picture associated with the non-IRAP picture or another RASL picture associated with an IRAP picture in decoding order is set equal to the first value.

In one embodiment, the first flag and the second flag may be set to a second value to indicate that the NAL unit for the non-IRAP picture does not include a RADL picture or a RASL picture. In one embodiment, the second value is zero. In one embodiment, neither the first flag nor the second flag is set to a first value for a non-IRAP picture.

At block 908 , a presentation order (eg, presentation order 510 of FIG. 5 ) for pictures included in the NAL unit is assigned based on a first flag or a second flag having a first value. . The presentation sequence may be used to generate or generate an image for display to a user on a display or screen of an electronic device (eg, a smart phone, tablet, laptop, personal computer, etc.).

In one alternative to the above, the NAL unit types for leading pictures and IRAP pictures are assigned as follows: two NAL unit types for leading pictures, RASL_NUT and RADL_NUT, and one for IRAP pictures. NAL unit type, i.e. IRAP_NUT.

In one embodiment, the mapping from IRAP NAL unit types to SAP types is as follows. When encountering a picture with an IRAP NAL unit type, the application determines the number of pictures with the RASL NAL unit type, and the IRAP picture and the first trailing picture that follows the IRAP picture in decoding order (e.g., a picture with a trailing NAL unit type). ) should count the number of pictures with a RADL NAL unit type between Depending on the RASL and RADL picture numbers, the following mapping is specified.

If the number of RASL pictures is greater than 0, the IRAP picture is SAP type 3. Otherwise, if the number of RASL pictures is 0 and the number of RADLs is greater than 0, the IRAP picture is SAP type 2. Otherwise (eg, the number of both RASL pictures and RADL pictures is 0), the IRAP picture is SAP type 1.

In another alternative, the NAL unit types for leading pictures and IRAP pictures are assigned as follows: Two NAL unit types for leading pictures, RASL_NUT and RADL_NUT. The definition of the NAL unit type for IRAP pictures is as follows. IDR (IDR_NUT): A NAL unit of an IRAP picture that is 0 or more RADL pictures and 0 RASL pictures in decoding order. CRA(CRA_NUT): NAL unit of an IRAP picture followed by one or more RASL pictures and zero or more RADL pictures in decoding order.

The mapping from IRAP NAL unit types to SAP types is as follows: CRA_NUT is SAP type 3.

When encountering a picture of type IDR_NUT, the application must check the picture that follows the IDR picture in decoding order. If the following picture is a picture with RADL_NUT, the IDR picture is SAP 2. Otherwise, the IDR picture is SAP 1.

When a picture is of type IDR_NUT, there is a restriction that the picture immediately following the IDR picture in decoding order may be a picture with RADL_NUT or Trailing_NUT.

In another alternative, the NAL unit types for leading pictures and IRAP pictures are assigned as follows: One NAL unit type for leading pictures: LP_NUT. The definition of NAL unit types for IRAP pictures is as follows: IDR (IDR_NUT): NAL unit of an IRAP picture that is 0 or more leading pictures and 0 RASL pictures that are RADL pictures in decoding order,

CRA (CRA_NUT): NAL unit of an IRAP picture followed by one or more leading pictures and zero or more RADL pictures that are RASL pictures in decoding order.

The mapping from IRAP NAL unit types to SAP is as follows: CRA_NUT is SAP type 3.

When encountering a picture of type IDR_NUT, the application must check the picture that follows the IDR picture in decoding order. If the picture that follows is a picture with LP_NUT, then the IDR picture is SAP 2. Otherwise, the IDR picture is SAP 1. When a picture is of type IDR_NUT, there is a restriction that the picture immediately following the IDR picture in decoding order may be a picture with LP_NUT or Trailing_NUT.

10 is a schematic diagram of a video coding device 1000 (eg, video encoder 20 or video decoder 30 ) in accordance with an embodiment of the present disclosure. Video coding device 1000 is suitable for implementing the disclosed embodiments described herein. The video coding device 1000 includes inlet ports 1010 and receiver units (Rx) 1020 for receiving data; a processor, logic unit, or central processing unit (CPU) 1030 that processes data; transmitter units (Tx) 1040 and egress ports 1050 for transmitting data; and a memory 1060 for storing data. The video coding device 1000 also includes a light coupled to inlet ports 1010 , receiver units 1020 , transmitter units 1040 and outlet ports 1050 for the outflow or ingress of optical or electrical signals. - electrical (OE) components and electro-optical (EO) components.

The processor 1030 is implemented by hardware and software. The processor 1030 may be implemented as one or more CPU chips, cores (eg, multi-core processors), field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), and digital signal processors (DSPs). . The processor 1030 communicates with the ingress ports 1010 , the receiver units 1020 , the transmitter units 1040 , the egress ports 1050 and the memory 1060 . The processor 1030 includes a coding module 1070 . Coding module 1070 implements the disclosed embodiments described above. For example, the coding module 1070 implements, processes, prepares, or provides various networking functions. Thus, the inclusion of the coding module 1070 provides substantial improvements to the functionality of the video coding device 1000 and affects the transformation of the video coding device 1000 to different states. Alternatively, coding module 1070 is implemented as instructions stored in memory 1060 and executed by processor 1030 .

The video coding device 1000 may also include input and/or output (I/O) devices 1080 for communicating data with a user. I/O devices 1080 may include an output device, such as a display for displaying video data, speakers for outputting audio data, or the like. I/O devices 1080 may also include input devices such as a keyboard, mouse, trackball, and/or a corresponding interface for interacting with such output devices.

Memory 1060 includes one or more disks, tape drives, and solid state drives, and overflows for storing programs as they are selected for execution, and for storing instructions and data read during program execution. It can be used as a data storage device. Memory 1060 may be volatile and/or non-volatile, and may be read-only memory (ROM), random access memory (RAM), ternary content-addressable memory (TCAM), and/or static random-access memory (SRAM). can be

11 is a schematic diagram of one embodiment of means 1100 for coding. In an embodiment, the means for coding 1100 is implemented in a video coding device 1102 (eg, video encoder 20 or video decoder 30 ). The video coding device 1102 comprises receiving means 1101 . The receiving means 1101 is configured to receive a picture to encode or receive a bitstream to decode. The video coding device 1102 comprises transmitting means 1107 coupled to receiving means 1101 . The transmitting means 1107 is configured to transmit the bitstream to the decoder or the decoded image to the display means (eg one of the I/O devices 1080 ).

The video coding device 1102 comprises storage means 1103 . The storage means 1103 is coupled to at least one of the receiving means 1101 or the transmitting means 1107 . The storage means 1103 is configured to store instructions. The video coding device 1102 also comprises processing means 1105 . The processing means 1105 is coupled to the storage means 1103 . The processing means 1105 is configured to execute the instructions stored in the storage means 1103 for performing the methods disclosed herein.

Also, it is to be understood that the steps of the exemplary methods disclosed herein are not necessarily performed in the order described, and that the order of steps in these methods is to be understood as illustrative only. Likewise, additional steps may be included in these methods, and certain steps may be omitted or combined in methods consistent with various embodiments of the present disclosure.

While several embodiments have been provided in this disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of the disclosure. These examples are to be regarded as illustrative and not restrictive, and are not intended to be limiting to the details given herein. For example, various elements or components may be combined or integrated into another system, and certain features may be omitted or not implemented.

In addition, techniques, systems, subsystems, and methods described and illustrated as separate or separate in various embodiments may be used in other systems, modules, techniques, or methods without departing from the scope of the present disclosure. may be combined or integrated with Other items shown or discussed as coupled or directly coupled or in communication with each other may be indirectly coupled or communicated via some interface, device, or intermediate component, whether electrical, mechanical, or otherwise. Other examples of changes, substitutions, and modifications will occur to those skilled in the art, and may be made without departing from the spirit and scope disclosed herein.

Claims (101)

A method of encoding a video bitstream implemented by a video encoder, comprising:
storing in a memory of the video encoder a set of less than five network abstraction layer (NAL) unit types available for video data;
selecting, by a processor of the video encoder, a NAL unit type from the set of less than five NAL unit types for a picture from the video data;
generating, by a processor of the video encoder, a video bitstream including a NAL unit corresponding to the selected NAL unit type and including an identifier identifying the selected NAL unit type; and
sending, by a transmitter of the video encoder, the video bitstream towards a video decoder;
How to include. The method of claim 1, wherein the set of less than 5 network abstraction layer (NAL) unit types have a leading and trailing pictures NAL unit type, a random access skipped leading (RASL) NAL unit type. An intra random access point (IRAP), an IRAP with a random access decodable leading (RADL) NAL unit type, and an IRAP without a leading pictures NAL unit type. The intra random access point of claim 1 , wherein the set of less than 5 network abstraction layer (NAL) unit types comprises: a leading and trailing pictures NAL unit type, a random access skipping type leading (RASL) NAL unit type ( IRAP), IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. Method according to claim 2 or 3, wherein both leading and trailing pictures are assigned the leading and trailing pictures NAL unit type. The method according to any one of claims 2 or 3, wherein an IRAP with a RASL NAL unit type is selected for an IRAP picture followed by one or more RASL pictures and zero or more RADL pictures in decoding order. The method of claim 5 , wherein the IRAP picture is referred to as a clean random access (CRA) picture. 6. The method of claim 5, wherein the IRAP with a RASL NAL unit type is referred to as a clean random access (CRA) NAL unit type. 6. The method of claim 5, wherein the IRAP with a RASL NAL unit type is designated as IRAP_W_RASL. The method of claim 8 , wherein the IRAP_W_RASL designation corresponds to stream access point (SAP) type 3 in dynamic adaptive streaming over hypertext transfer protocol (DASH). The method according to claim 2 or 3, wherein the IRAP with a RADL NAL unit type is selected for an IRAP picture followed by one or more RADL pictures and zero RADL pictures in decoding order. The method of claim 10 , wherein the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture. 11. The method of claim 10, wherein the IRAP with a RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with a RADL NAL unit type. 11. The method of claim 10, wherein the IRAP with a RADL NAL unit type is designated as IRAP_W_RADL. The method of claim 13 , wherein the IRAP_W_RADL corresponds to a stream access point (SAP) type 2 in dynamic adaptive streaming over hypertext transfer protocol (DASH). The method according to claim 2 or 3, wherein the IRAP without leading pictures NAL unit type is selected for an IRAP picture not followed by a leading picture in decoding order. 16. The method of claim 15, wherein the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture. 16. The method of claim 15, wherein the IRAP without leading pictures NAL unit type is referred to as instantaneous decoder refresh (IDR) without leading pictures NAL unit type. 14. The method of claim 13, wherein the IRAP without leading pictures NAL unit type is designated as IRAP_N_LP. The method of claim 18 , wherein the IRAP_N_LP designation corresponds to stream access point (SAP) type 1 in dynamic adaptive streaming over hypertext transfer protocol (DASH). A method of decoding a coded video bitstream implemented by a video decoder, comprising:
storing in a memory of the video decoder a set of less than five network abstraction layer (NAL) unit types available for video data;
receiving, by a receiver of the video decoder, a coded video bitstream comprising a NAL unit and an identifier;
determining, by a processor of the video decoder, a NAL unit type used to encode a NAL unit based on the identifier from a set of less than five NAL unit types; and
allocating, by the processor of the video decoder, a presentation order for pictures included in the NAL unit based on the determined NAL unit type;
How to include. 21. The intra-random access point of claim 20, wherein the set of less than five network abstraction layer (NAL) unit types comprises: a leading and trailing pictures NAL unit type, a random access skipping type leading (RASL) NAL unit type. IRAP), IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. 21. The intra-random access point of claim 20, wherein the set of less than five network abstraction layer (NAL) unit types comprises: a leading and trailing pictures NAL unit type, a random access skipping type leading (RASL) NAL unit type. IRAP), IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. 23. A method according to claim 21 or 22, wherein both leading and trailing pictures are assigned the leading and trailing pictures NAL unit type. 23. The method according to claim 21 or 22, wherein the IRAP with a RASL NAL unit type is determined for an IRAP picture followed by one or more RASL pictures and zero or more RADL pictures in decoding order. 25. The method of claim 24, wherein the IRAP picture is referred to as a clean random access (CRA) picture. 25. The method of claim 24, wherein the IRAP with a RASL NAL unit type is referred to as a clean random access (CRA) NAL unit type. 25. The method of claim 24, wherein the IRAP with a RASL NAL unit type is designated IRAP_W_RASL. 28. The method of claim 27, wherein the IRAP_W_RASL designation corresponds to stream access point (SAP) type 3 in dynamic adaptive streaming over hypertext transfer protocol (DASH). 23. The method according to claim 21 or 22, wherein the IRAP with a RADL NAL unit type is determined for an IRAP picture followed by one or more RADL pictures and zero RADL pictures in decoding order. 30. The method of claim 29, wherein the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture. 30. The method of claim 29, wherein the IRAP with a RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with a RADL NAL unit type. 30. The method of claim 29, wherein the IRAP with a RADL NAL unit type is designated as IRAP_W_RADL. 33. The method of claim 32, wherein the IRAP_W_RADL corresponds to stream access point (SAP) type 2 in dynamic adaptive streaming over hypertext transfer protocol (DASH). 23. The method according to claim 21 or 22, wherein the IRAP without leading pictures NAL unit type is determined for an IRAP picture not followed by a leading picture in decoding order. 35. The method of claim 34, wherein the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture. 35. The method of claim 34, wherein the IRAP without leading pictures NAL unit type is referred to as instantaneous decoder refresh (IDR) without leading pictures NAL unit type. 35. The method of claim 34, wherein the IRAP without leading pictures NAL unit type is designated as IRAP_N_LP. 38. The method of claim 37, wherein the IRAP_N_LP designation corresponds to stream access point (SAP) type 1 in dynamic adaptive streaming over hypertext transfer protocol (DASH). An encoding device comprising:
a memory comprising a set of instructions and less than five network abstraction layer (NAL) unit types available for video data;
a processor coupled to the memory and configured to implement the instructions, the instructions causing an encoding device to:
select a NAL unit type from a set of less than 5 NAL unit types for a picture from the video data;
generate a video bitstream that includes a NAL unit corresponding to the selected NAL unit type and includes an identifier identifying the selected NAL unit type; and
A transmitter coupled to the processor and configured to transmit the video bitstream towards the video decoder.
An encoding device comprising: 40. The method of claim 39, wherein the set of less than five Network Abstraction Layer (NAL) unit types comprises: a leading and trailing pictures NAL unit type, an intra random access point having a random access skipping leading (RASL) NAL unit type ( IRAP), IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. 40. The method of claim 39, wherein the set of less than five Network Abstraction Layer (NAL) unit types comprises: a leading and trailing pictures NAL unit type, an intra random access point having a random access skipping leading (RASL) NAL unit type ( IRAP), IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. 42. Encoding device according to claim 40 or 41, wherein both leading and trailing pictures are assigned the leading and trailing pictures NAL unit type. 42. The encoding device according to claim 40 or 41, wherein an IRAP with a RASL NAL unit type is selected for an IRAP picture followed by one or more RASL pictures and zero or more RADL pictures in decoding order. 44. The encoding device of claim 43, wherein the IRAP picture is referred to as a clean random access (CRA) picture. 44. The encoding device of claim 43, wherein the IRAP with a RASL NAL unit type is referred to as a clean random access (CRA) NAL unit type. 44. The device of claim 43, wherein the IRAP with a RASL NAL unit type is designated as IRAP_W_RASL. 47. The encoding device of claim 46, wherein the IRAP_W_RASL designation corresponds to stream access point (SAP) type 3 in dynamic adaptive streaming over hypertext transfer protocol (DASH). . 42. The encoding device according to claim 40 or 41, wherein the IRAP with a RADL NAL unit type is selected for an IRAP picture followed by one or more RADL pictures and zero RADL pictures in decoding order. 49. The encoding device of claim 48, wherein the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture. 49. The device of claim 48, wherein the IRAP with a RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with a RADL NAL unit type. 49. The device of claim 48, wherein the IRAP with a RADL NAL unit type is specified as IRAP_W_RADL. The encoding device of claim 51 , wherein the IRAP_W_RADL corresponds to stream access point (SAP) type 2 in dynamic adaptive streaming over hypertext transfer protocol (DASH). 42. The encoding device according to claim 40 or 41, wherein the IRAP without leading pictures NAL unit type is selected for an IRAP picture not followed by a leading picture in decoding order. 54. The encoding device of claim 53, wherein the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture. 54. The encoding device of claim 53, wherein the IRAP without leading pictures NAL unit type is referred to as instantaneous decoder refresh (IDR) without leading pictures NAL unit type. 54. The encoding device of claim 53, wherein the IRAP without leading pictures NAL unit type is designated as IRAP_N_LP. 57. The encoding device of claim 56, wherein the IRAP_N_LP designation corresponds to stream access point (SAP) type 1 in dynamic adaptive streaming over hypertext transfer protocol (DASH). . A decoding device comprising:
a receiver configured to receive a coded video bitstream comprising a NAL unit and an identifier;
a memory coupled to the receiver for storing instructions and a set of less than five network abstraction layer (NAL) unit types available for video data; and
a processor coupled to the memory and configured to execute the instructions
wherein the instructions cause the decoding device to:
determine, from a set of less than five NAL unit types, a NAL unit type used to encode the NAL unit based on the identifier;
and assign a presentation order to pictures included in the NAL unit based on the determined NAL unit type. 59. The intra-random access point of claim 58, wherein the set of less than five network abstraction layer (NAL) unit types comprises: a leading and trailing pictures NAL unit type, a random access skipping type leading (RASL) NAL unit type. IRAP), IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. 59. The intra-random access point of claim 58, wherein the set of less than five network abstraction layer (NAL) unit types comprises: a leading and trailing pictures NAL unit type, a random access skipping type leading (RASL) NAL unit type. IRAP), IRAP with Random Access Decodable Leading (RADL) NAL unit type, and IRAP without leading pictures NAL unit type. The decoding device according to claim 59 or 60, wherein both leading and trailing pictures are assigned the leading and trailing pictures NAL unit type. 61. The decoding device according to claim 59 or 60, wherein the IRAP with a RASL NAL unit type is selected for an IRAP picture followed by one or more RASL pictures and zero or more RADL pictures in decoding order. 63. The decoding device of claim 62, wherein the IRAP picture is referred to as a clean random access (CRA) picture. 63. The decoding device of claim 62, wherein the IRAP with a RASL NAL unit type is referred to as a clean random access (CRA) NAL unit type. 63. The decoding device of claim 62, wherein the IRAP with a RASL NAL unit type is designated as IRAP_W_RASL. 66. The decoding device of claim 65, wherein the IRAP_W_RASL designation corresponds to stream access point (SAP) type 3 in dynamic adaptive streaming over hypertext transfer protocol (DASH). . The decoding device according to claim 59 or 60, wherein the IRAP with a RADL NAL unit type is selected for an IRAP picture followed by one or more RADL pictures and zero RADL pictures in decoding order. 68. The decoding device of claim 67, wherein the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture with a RADL picture. 68. The decoding device of claim 67, wherein the IRAP with a RADL NAL unit type is referred to as an instantaneous decoder refresh (IDR) with a RADL NAL unit type. 68. The decoding device of claim 67, wherein the IRAP with a RADL NAL unit type is designated as IRAP_W_RADL. 71. The decoding device of claim 70, wherein the IRAP_W_RADL corresponds to a stream access point (SAP) type 2 in dynamic adaptive streaming over hypertext transfer protocol (DASH). The decoding device according to claim 59 or 60, wherein the IRAP without leading pictures NAL unit type is selected for an IRAP picture not followed by a leading picture in decoding order. 73. The device of claim 72, wherein the IRAP picture is referred to as an instantaneous decoder refresh (IDR) picture without a leading picture. 73. The decoding device of claim 72, wherein the IRAP without leading pictures NAL unit type is referred to as instantaneous decoder refresh (IDR) without leading pictures NAL unit type. 73. The decoding device of claim 72, wherein the IRAP without leading pictures NAL unit type is designated as IRAP_N_LP. 76. The decoding device of claim 75, wherein the IRAP_N_LP designation corresponds to stream access point (SAP) type 1 in dynamic adaptive streaming over hypertext transfer protocol (DASH). . A method of encoding a video bitstream implemented by a video encoder, comprising:
generating, by a processor of a video encoder, a bitstream comprising a network abstraction layer (NAL) unit for a non-intra random access point (non-IRAP) picture associated with an intra random access point (IRAP) picture step;
When the NAL unit for the non-IRAP picture includes a random access decodable leading (RADL) picture, by the processor of the video encoder, a first flag in the bitstream is set to a first value to do;
When the NAL unit for the non-IRAP picture includes a random access skipped leading (RASL) picture, by the processor of the video encoder, a second flag in the bitstream is set to the first value. setting; and
sending, by a transmitter of the video encoder, the video bitstream towards a video decoder;
How to include. 78. The method of claim 77, wherein the first flag is designated as RadlPictureFlag and the second flag is designated as RaslPictureFlag. 78. The method of claim 77, wherein the first value is one (1). 80. The method of claim 78 or 79, wherein the non-IRAP picture comprises a leading picture. 80. The method of claim 78 or 79, wherein the non-IRAP picture comprises a trailing picture. 78. The method of claim 77, wherein the first flag is set equal to the first value when a picture order count (POC) value of the non-IRAP picture is less than a POC value of the IRAP picture. 78. The method of claim 77, wherein each reference picture list for the non-IRAP picture does not contain any pictures other than an IRAP picture associated with the non-IRAP picture or another RADL picture associated with the IRAP picture. a flag is set equal to the first value. 78. The method of claim 77, wherein the second flag is set equal to the first value when a picture order count (POC) value of the non-IRAP picture is less than a POC value of the IRAP picture. 78. The method of claim 77, wherein the reference picture list for the non-IRAP picture includes at least one reference picture that precedes the IRAP picture associated with the non-IRAP picture or another RASL picture associated with the IRAP picture in decoding order. when the second flag is set equal to the first value. 78. The method of claim 77, further comprising setting the first flag and the second flag to a second value indicating that the NAL unit for the non-IRAP picture does not include the RADL picture or the RASL picture. How to. 78. The method of claim 77, wherein neither the first flag nor the second flag is set to the first value for the non-IRAP picture. A method of decoding a coded video bitstream implemented by a video decoder, comprising:
a first flag, a second flag and a network abstraction layer (NAL) unit for a non-intra random access point (non-IRAP) picture associated with an intra random access point (IRAP) picture by the receiver of the video decoder receiving a coded video bitstream;
When the first flag in the bitstream is set to a first value by the processor of the video decoder, the NAL unit for the non-IRAP picture includes a random access decodable leading (RADL) picture deciding to do;
By the processor of the video decoder, when the second flag in the bitstream is set to the first value, the NAL unit for the non-IRAP picture selects a random access skipped leading (RASL) picture. determining to include; and
Allocate, by the processor of the video decoder, a presentation order for the pictures included in the NAL unit based on the first flag or the second flag having the first value, and based on the assigned presentation order decoding the NAL unit by
How to include. 89. The method of claim 88, wherein the first flag is designated as RadlPictureFlag and the second flag is designated as RaslPictureFlag. 89. The method of claim 88, wherein the first value is one (1). 91. The method of claim 89 or 90, wherein the non-IRAP picture comprises a leading picture. 91. The method of claim 89 or 90, wherein the non-IRAP picture comprises a trailing picture. 89. The method of claim 88, wherein the first flag is set equal to the first value when a picture order count (POC) value of the non-IRAP picture is less than a POC value of the IRAP picture. 89. The method of claim 88, wherein when each reference picture list for the non-IRAP picture does not contain any pictures other than an IRAP picture associated with the non-IRAP picture or another RADL picture associated with the IRAP picture. a flag is set equal to the first value. 89. The method of claim 88, wherein the second flag is set equal to the first value when a picture order count (POC) value of the non-IRAP picture is less than a POC value of the IRAP picture. 89. The method of claim 88, wherein the reference picture list for the non-IRAP picture includes at least one reference picture that precedes, in decoding order, the IRAP picture associated with the non-IRAP picture or another RASL picture associated with the IRAP picture. when the second flag is set equal to the first value. 89. The method of claim 88, further comprising setting the first flag and the second flag to a second value indicating that the NAL unit for the non-IRAP picture does not include the RADL picture or the RASL picture. How to. 89. The method of claim 88, wherein neither the first flag nor the second flag is set to the first value for the non-IRAP picture. A coding device comprising:
a receiver configured to receive a bitstream to decode;
a transmitter coupled to the receiver and configured to transmit a decoded image to a display;
a memory coupled to at least one of the receiver or the transmitter and configured to store instructions; and
A processor coupled to the memory and configured to execute instructions stored in the memory to perform the method of any one of claims 1-38 and 77-98.
A coding device comprising a. As a system,
encoder; and
A decoder in communication with the encoder
, wherein the encoder or the decoder comprises the decoding device, encoding device or coding apparatus of any one of claims 39 to 76 and 99. As a means for coding,
receiving means configured to receive a bitstream to be decoded;
transmitting means coupled to the receiving means and configured to transmit the decoded image to the display means;
storage means coupled to at least one of the receiving means or the transmitting means and configured to store instructions; and
97. Processing means coupled to said storage means and configured to execute instructions stored in said storage means to perform the method of any one of claims 1-38 and 77-98.
Means for coding comprising

Images